https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz Submit your work here en-us 2021-05-27 09:40:23 UTC 2025-10-11 11:52:53 UTC hello@padlet.com https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658176675 The bicycle had a constant acceleration for the first 1 seconds.
From 10 to 20 seconds, the bicycle had constant decreasing acceleration.]]> 2021-07-22 09:43:58 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658176675 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658176792 The acceleration remains constant for the first 10 seconds before increasing  decreasing constant rate from 10 seconds to 20 seconds ]]> 2021-07-22 09:44:11 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658176792 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658176818 1a. There is a constant acceleration for the first 10s. Between 10-20s, the acceleration of the man decreases.

bi. 3.87m/s^2 👍
ii. 40.7m/s 👍]]> 2021-07-22 09:44:14 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658176818 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658177084 1a. From 0s to 10s, the man accelerates at a constant rate. (constant acceleration)

From 10s to 20s, the man accelerates at a decreasing rate (decreasing acceleration)

1bi. 3.87ms^-2 👍
1bii. 21.3ms^-1 X (40.7ms^-1) 👍]]> 2021-07-22 09:44:44 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658177084 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658178887 3.87m/s^2 👍
1bii)40.7m/s 👍]]> 2021-07-22 09:47:53 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658178887 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658180003 2a. Point where diagonal AC and BD intersect above B 👍
2b. Line of action of weight directly above B 👍
2c. The block can be tilted to a larger angle about B. At a lower height, the centre of gravity is lowered. This increases the stability of the block and hence a larger moment about B is required to create a toppling moment. 👍]]> 2021-07-22 09:50:00 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658180003 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658181508 3.87m/s^{2 👍}
40.7m/s 👍]]> 2021-07-22 09:53:11 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658181508 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658182046 At the point where the line of action of weight is directly above point B. 👍]]> 2021-07-22 09:54:17 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658182046 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658183334 2a. Place the 'X' at the point where the diagonals of AC and BD intersect 👍

b. The line of action of weight, w is directly above B 👌

c. When the height of the block decreases, the centre of gravity is lowered, causing the block to be more stable. This increases the moment used to topple the block  The block can be tilted more (or at greater angle) before it topples over.]]> 2021-07-22 09:57:07 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658183334 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658183606 Since the height is lowered, the center of gravity is lower thus the block is more stable. Therefore, the angle at which the box can be tilted before toppling over is greater. 👌]]> 2021-07-22 09:57:45 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658183606 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658184600 3a. 103000Pa X (122000Pa)
3b. As the flask the starts to cool, air molecules have lower kinectic energy ✔ and move slower. Hence, the frequency of collisions between the inner surface of the flask decreases 👌 and the molecules exert a lower force 👍on the inner surface of the flask. Since pressure is defined as a force per unit area, a decrease in the magnitude of the force leads to a decrease in pressure in the flask ✔]]> 2021-07-22 09:59:30 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658184600 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658184959 4a Work is when a force produces a motion perpendicular to the force

Product of force and distance travelled by object
in the direction of the force.

4b. 16.3ms^-1 👌
4ci. 80.0N ❌ (100J)
4cii. 255J ❌  (165J)
4d. Height AB ❌ (above AB)

]]> 2021-07-22 10:00:20 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658184959 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658185769 122000Pa]]> 2021-07-22 10:02:07 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658185769 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658185820 Where the line of action of the weight is directly above point B 👍]]> 2021-07-22 10:02:13 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658185820 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658186085 The lower height causes the centre of gravity to be lowered thus the block becomes more stable and a force can tilt the rectangle at a larger angle is needed to push it topple it over ]]> 2021-07-22 10:02:46 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658186085 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658187501 3a. 130000 Pa X (122000Pa)

b. As the air molecules in the flask starts to cool, they have a lower kinetic energy 👌 so the move slower. Therefore the frequency of collisions between the air molecules and the wall of the flask decreases.👍 The air molecules also exert a smaller force on the walls of the flask.✔ As pressure is force per unit area, when the force decreases, the pressure decreases. This cause a drop in mercury level.👍]]> 2021-07-22 10:05:38 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658187501 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658188677 As air in the flask cools, the air molecules have a lower kinetic energy 👍 thus they move slower. Since pressure is the force acting per unit area, the air molecules will hit the wall of the container with a lower force 👌and have less frequent collisions with the walls of the flask✔ thus resulting in a decrease in pressure. the decrease in pressure in the flask causes the difference in mercury levels to decrease. 👌]]> 2021-07-22 10:08:06 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658188677 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658193066 5ai. 3V is the potential differnece across a beaker of liquid of unknown temperatue and the surrounding temperature. Since the temperature of the liquid id unknown, it is not possible to determine the temperature of surrounding air 👌

5aii. 24°C ✔
5b. The thermometer will show a higher  LOWER temperature. This is because the capillary has a smaller WIDER BORE space which means some mercury may be pushed upwards. Hence, a higher temperature may be displayed]]> 2021-07-22 10:16:07 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658193066 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658193564 work is when a force acting on an object produces a motion X

Product of force and distance travelled by object
in the direction of the force.]]> 2021-07-22 10:17:12 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658193564 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658194289 As the air in the flask cools, the molecule lose kinetic energy 👍 and move slower, causing the molecule to collide with the wall of the flask less often👌, thus exerting a lower net force on the flask👍. Since pressure is defined as a force per unit area, this reduces the pressure on the walls of the flask which will cause the difference in mercury level to decrease

]]> 2021-07-22 10:18:47 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658194289 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658194946 6a. Highest: 1×10^9 Hz
Lowest: 4.17×10^8 Hz ❌ (check your powers of 10)     (4.17x10^8 Hz)

6bi. Infrared  👌
6bii. Remote controls 👌

]]> 2021-07-22 10:20:24 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658194946 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658196127 20.5m/s ❌(16.3m/s)]]> 2021-07-22 10:23:01 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658196127 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658196254 4a.  Work is when an applied force moves an object X

Product of force and distance travelled by object
in the direction of the force.

b. 15.5m/s ❌ (16.3m/s) 

ci.  100J ✔
ii.  165J ✔

d. The same height as the line AB ❌ (above AB)]]> 2021-07-22 10:23:20 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658196254 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658197568 100J ✔]]> 2021-07-22 10:26:11 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658197568 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658198350 Work is the energy transferred when a force acts on an object and moves it? X

Product of force and distance travelled by object
in the direction of the force.]]> 2021-07-22 10:28:08 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658198350 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658199026 8.31m/s ❌]]> 2021-07-22 10:29:35 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658199026 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658200850 100 J ✔
165 J ✔]]> 2021-07-22 10:33:33 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658200850 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658201850 7ai. 22.1° 👌
7aii. The angle of incidence at R2 is greater than the critical angle. Light was also travelling from an optically denser to an optically less dense medium. Hence, the light ray underwent total internal reflection, explaining why the light ray at R2 does not exit the bottle. 👌
7b. In fig 7.2, light undergoes total internal reflection as they hit the inner surface of the plastic bottle causing ALL of the light entering the bottle to exit via the base of the bottle and brightens the entire room.  which allows light to spread out in all directions. In fig 7.3, light just shines into the house without undergoing total internal reflection so light is not spread out in all directions. So light only brighten certain portion of the house
7c. Radiation. There is no medium and only radiation does not require a medium. So thermal energy could travel through space to reach the boy from the sun 👌]]> 2021-07-22 10:35:36 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658201850 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658203732 165J ✔]]> 2021-07-22 10:39:55 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658203732 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658204375 8bi. Iron 👌
8bii. Iron is a soft magnetic material so it is able to be magnitised and demagnetise easily. Hence when current passes through thr coil, the iron gets magnetised quickly, allowing sound to be projected out of the megaphone quickly

]]> 2021-07-22 10:41:22 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658204375 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658207844 9a. 0.0825m 👌
9b. Minimum distance= 75000m
Sound wave emmision device is better becuase the beeping only starts closer to the wall so the driver knows when he is approaching the wall 👌]]> 2021-07-22 10:49:15 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658207844 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658208914 at AB ❌(C?) (above AB)]]> 2021-07-22 10:51:35 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658208914 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658209019 12 m ❌ (above AB)]]> 2021-07-22 10:51:49 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658209019 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658209384 The temperature of the liquid in the beaker is unknown therefore the 3V which is the p.d across the beaker of water and surrounding air is not useful.❌ The P.D. makes use of the difference in temperature between the hot and cold junction and telling temperature is impossible since temperature of liquid is unknown. ]]> 2021-07-22 10:52:42 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658209384 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658210445 5ai.  As the cold junction is placed in a liquid with and unknown temperature and the hot junction is placed in the surrounding air, the temperature of the unknown liquid cannot be found as the temperature of the surrounding air and liquid are both unknown , hence the p.d of 3V is useless ❌ The P.D. makes use of the difference in temperature between the hot and cold junction and telling temperature is impossible since temperature of liquid is unknown.

ii. 24 degrees celsius ✔

b. The thermometer would reflect an inaccurate reading as the space between the capillary changes from small to large so the temperature would be lower 👌



]]> 2021-07-22 10:55:04 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658210445 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658211192 As the liquid is of an unknown temperature, we cannot use the thermocouple to measure the temperature of the surrounding air through the potential difference ❌The P.D. makes use of the difference in temperature between the hot and cold junction and telling temperature is impossible since temperature of liquid is unknown.

24C ✔]]> 2021-07-22 10:56:42 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658211192 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658212079 24 degree celsius ✔]]> 2021-07-22 10:58:05 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658212079 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658214141 The non-uniform capillary walls may cause the temperature reading not to increase proportionally with the temperature 👌 The temperature reading after the fault will be lower than the actual reading]]> 2021-07-22 11:02:37 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658214141 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658214495 The capillary walls are not evenly distanced and the smaller WIDER space between the walls causes the reading to be higher LOWER. Therefore this leads to an inaccurate reading. ]]> 2021-07-22 11:03:29 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658214495 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658215411 4.17(10^5)Hz ❌ (check your powers of 10)]]> 2021-07-22 11:05:37 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658215411 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658216567 4.17x10⁸ ❌ (check your powers of 10)]]> 2021-07-22 11:08:41 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658216567 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658216571 infrared 👌]]> 2021-07-22 11:08:42 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658216571 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658217223 Used in remote controls. 👌]]> 2021-07-22 11:10:26 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658217223 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658217298 6a.  4.17x10^8 Hz ❌ (check your powers of 10) (4.17 x 10^14 Hz)

bi. Infrared 👌

ii. thermometer 👌]]> 2021-07-22 11:10:38 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658217298 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658217978 22.1degrees 👌]]> 2021-07-22 11:12:28 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658217978 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658218071 Light is travelling from an optically denser medium to an optically less dense medium and the angle of incidence of R2 is larger than the critical angle. R2 undergoes total internal reflection thus it does not exit the bottle after the first refraction. 👌]]> 2021-07-22 11:12:43 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658218071 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658219343 In fig 7.2, the light that enters the bottle undergoes total internal reflection causing it to causing ALL of the light entering the bottle to exit via the base of the bottle and brightens the entire room.  spread in different directions around the room whereas in Fig7.3, light does not undergo total internal reflection and so brightens only part of the room depending on the position of the sun. does not spread around the room.]]> 2021-07-22 11:15:54 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658219343 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658219581  Infrared 👌
Remote control  👌]]> 2021-07-22 11:16:20 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658219581 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658219651 22.1 degree 👌
The angle of incidence is greater than the critical angle and the light is travelling from the optically denser to the optically less dense medium, thus the light ray undergoes total internal reflection and does not exit the bottle 👌]]> 2021-07-22 11:16:31 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658219651 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658219949 7ai. 22.1 degrees 👌

ii. The angle of incidence, i is geater than the critical angle, c so the light ray undergoes total internal reflection. Moreover, the light ray is also travelling from an optically denser medium to an optically less dense medium 👌

b. For fig 7.2 as the light ray is travelling from an optically less dense medium to an optically denser medium, and the angle of incidence is greater than the critical angle, total internal reflection occurs and causing ALL of the light entering the bottle to exit via the base of the bottle and brightens the entire room  it spreads out over the entire house area ❌. However, for fig 7.3,  the light ray passes through the plastic sheet and shines straight into the house without spreading out 👌

7c. Radiation as it does not require a medium to reach the boy so thermal energy could travel through a vacuum in outerspace from the sun. 👌]]> 2021-07-22 11:17:18 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658219949 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658220966 Radiation as it does not require a medium to travel in. Thus the thermal energy is able to travel from the sun through space, where there is no medium, and into the house on earth to reach the boy. 👌]]> 2021-07-22 11:19:47 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658220966 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658221768 In figure 7. 2 the light undergoes total internal reflection causing ALL of the light entering the bottle to exit via the base of the bottle and brightens the entire room. and spreads out ❌ but in figure 7.3 the light does not undergo total internal reflection and thus doesn't spread out  so brightens only part of the room depending on the position of the sun.]]> 2021-07-22 11:21:29 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658221768 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658222094 the empty space between the field lines.]]> 2021-07-22 11:22:09 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658222094 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658222226 Radiation can travel without a medium to reach the boy because the infra-red rays must pass through vacuum in outerspace between the sun and the boy.]]> 2021-07-22 11:22:27 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658222226 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658223111 Iron 👌]]> 2021-07-22 11:24:12 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658223111 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658223609 it is a soft magnetic material and is able to be magnetized quickly.  👌]]> 2021-07-22 11:25:15 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658223609 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658223884 10a. 35.1Ω 👌
10b. $4.29 👌]]> 2021-07-22 11:25:49 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658223884 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658224846 0.0825m 👌]]> 2021-07-22 11:27:49 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1658224846 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663989195 8aii. The tangent line in the middle

bi. Soft iron 👌

ii.  Soft iron is a material that is easy to magnetize and demangetise so when current flows through the coil, A gets magnetised easily and this enable the sound to be transmitted quickly. 👌]]> 2021-07-29 10:03:48 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663989195 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663989290 a. 4.17x10^14 Hz 👌
bi. Infrared 👌
ii. remote controls 👌]]> 2021-07-29 10:04:04 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663989290 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663991396 11ai. 2381kg 👌
11aii. 3.10x10^8J 👌
11aiii. 25800s 👌
b) It takes 6h to heat up the water in FIji but the average daily sunshine is 4h. Hence there is insufficient solar energy to heat up the water in FIji 👌
c. A metal. Becuase metals are good conductors of heat 👌
 


]]> 2021-07-29 10:09:25 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663991396 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663993633 The sound wave emission device is better as the minimum distance at which the sensor can detect the sound delay for the equipment that  transmits and receives radio waves is 75000m which is much larger as compared to 0.0825m.  👌]]> 2021-07-29 10:15:10 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663993633 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663994305 in the middle between the two magnets]]> 2021-07-29 10:16:48 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663994305 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663994486 iron 👌
soft magnetic material that can be easily magnetised and demagnetised 👌]]> 2021-07-29 10:17:14 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663994486 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663994924 ai. 22.1 degrees 👌

ii. The angle of incidence is greater than the critical angle and the light ray is travelling from an optically denser medium to an optically less dense medium, thus total internal reflection occurs. 👌

b. In Fig. 7.2, total internal reflection occurs and causing ALL of the light entering the bottle to exit via the base of the bottle and brightens the entire room the light is able to spread out over the house. However, in Fig 7.3, total internal reflection does not occur and thus the light is not able to be spread out  so brightens only part of the room depending on the position of the sun

c. Radiation as it can travel through vacuum ❌ Too brief

Radiation as it does not require a medium to reach the boy so thermal energy could travel through a vacuum in outerspace from the sun]]> 2021-07-29 10:18:36 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663994924 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663995164 0.0825m 👌]]> 2021-07-29 10:19:21 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663995164 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663995396 9a. 0.0825m 👌

b. The sound wave emission device is better because the sensor is able to produce a beeping sound when the driver is very close to the wall than compared to the radio waves emission device which produces a beep is as far as 75000m 👌]]> 2021-07-29 10:19:57 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663995396 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663995476 35.1ohm 👌]]> 2021-07-29 10:20:11 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663995476 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663997056 $4.29 👌]]> 2021-07-29 10:24:18 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663997056 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663997469 12a. Ohm's Law states that the current passing through a conductor is directly proportional to the potential difference between its ends provided that the physical conditions and temperature remain constant 👌
12b. The I/V graph shows a curve instead of a linear line 👌
c) The resistance increases. As V increases, the gradient which is 1/R  decreases thus resistance will increase 👌
di) rheostat 👌
dii) The rheostat can be set to a higher resistance to increase the effective resistance. Since V=RI and the voltage remains the same, the current will decrease 👍
ei) 0.05A ✔
eii)0.0125A ✔]]> 2021-07-29 10:25:20 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663997469 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663998589 bi. Iron 👌
ii. It is easily magnetized and demagnetized 👌]]> 2021-07-29 10:28:12 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663998589 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663999435 the sound wave emission device is better because it can transmit at a smaller distance

Minimum distance
= 0.5(300000000m/s × 0.0005s)
= 75 000 m
75000 m  minimum distance is NOT practical for parking purpose.


]]> 2021-07-29 10:30:21 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663999435 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663999952 a. 0.0825m 👌
b. The sound wave emission device is better as it only transmits a signal when the car is 0.0825m away from the wall as compared to the radio wave emission device that transmits a signal when the car is 75000m away from the wall. 👌]]> 2021-07-29 10:31:20 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1663999952 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664000640 13a) DCBA. Using the Fleming Left Hand Rule, the thumb which represents the direction of induced force points upwards (along DC) and downwards (along BA) and the second index finger which represents the direction of magnetic field is to the right. Hence, the middle finger which represents direction of current points into the paper for the left side of the coil (D-->C) and (B-->A) on the right side of the coil. Hence, current flows in DCBA

c) Component X is the split ring commutator that reverses the direction of current every 1/2 revolution (when the coil is in a vertical position)  such that a continuous upwards force on the left side of the coil and a continuous downward force on the right side allowing the coil to complete full rotation.
 
d) The battery has been flipped over such that the positions of their terminals are switched and a stronger battery was used 👍

]]> 2021-07-29 10:32:57 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664000640 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664001130 35.1 ohm 👌]]> 2021-07-29 10:33:50 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664001130 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664001189 2381kg 👌]]> 2021-07-29 10:34:00 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664001189 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664001766 10a. 35.1 ohm 👌

b. $4.29 👌

]]> 2021-07-29 10:35:08 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664001766 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664006121 13ai) Positively charged 👌
13aiii) Gravitational pull form Earth ✔✔
bi)  Electrons from earth are attracted up to the ball 👌
bii) The sphere moves towards the positively charged plate. The ball is has a net negative charge and since unlike charges attract, the ball is attracted to the plate 👍
iii) negative charges spread out evenly 👌]]> 2021-07-29 10:45:59 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664006121 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664007531 $4.29 👌]]> 2021-07-29 10:48:59 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664007531 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664009532 a. 35.1 ohm 👌
b. $4.29 👌]]> 2021-07-29 10:53:55 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664009532 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664011164 11ai. 2381kg  👌

ii. 3.10x10^8 J 👌

iii. 25800s

b. In Fiji, it uses 6 hours to heat up the water. However, the average daily sunlight is only 4 hours so there is insufficient heat energy absorbed to heat up the water. 👌

c. Iron as iron is a good conductor of heat to it can absorb a large amount to heat to heat the water 👌(Note: Iron tend to rust in contact with water so better to use copper)

]]> 2021-07-29 10:58:30 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664011164 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664011885 ai. 2381kg 👌
ii. 3.10x10^8J 👌
iii. 25800s 👌

b. In Fiji, 6h is required to heat up the water , but Fiji only receives an average of 4h of sunshine a day. Therefore, not enough solar energy is able to be absorbed and the heating system is unable to maintain the indoor temperature of 25 degrees celsius. 👌

c. Copper as it is a good conductor of heat. 👌]]> 2021-07-29 11:00:26 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664011885 gregorywong_sg https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664012742 2021-07-29 11:02:43 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664012742 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664013999 2381 kg 👌
3.10x10⁸ J 👌
25800 sec 👌
There is not enough hours of sunlight to provide sufficient energy to heat up the water as the daily sunshine is four hours but six hours are needed to heat up water]]> 2021-07-29 11:06:19 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664013999 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664016153 3.10 x 10^8 J 👌]]> 2021-07-29 11:10:49 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664016153 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664018223 25800s 👌]]> 2021-07-29 11:16:00 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664018223 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664018524 It takes 6hours to heat up water. However the average daily sunshine is only 4 hours. thus there is insufficient solar energy to heat up the water. 👌]]> 2021-07-29 11:16:45 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664018524 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664020852 a. The current passing through a conductor is directly proportional to the potential difference across the two points.

b. The graph shows a curve instead of a straight line

c. When the potential difference increases, the resistance also increases.]]> 2021-07-29 11:22:05 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664020852 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664021128 stainless steel. it is a good conductor of heat. (note: steel tends to rust and corrode in contact with water and oxygen)]]> 2021-07-29 11:22:41 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664021128 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664021369 Ohm's law states that the current passing through a conductor is directly proportional to the potential difference  between its ends provided all other physical conditions (e.g. temperature) stays constant.]]> 2021-07-29 11:23:19 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664021369 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664021946 the graph is not a linear line and is a curve. 👍 ]]> 2021-07-29 11:24:35 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664021946 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664022145 when the potential difference increases, the resistance of the lamp also increases.

Using Fig.12.2, state and explain the change to the resistance of the lamp

Note: Ratish, you need to state the changes in the gradient from the graph and link it to the resistance. Hence, as the potential difference increases, the gradient (1/R) of the graph decreases (become gentler). Hence, the value of R increases. ]]> 2021-07-29 11:25:02 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664022145 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664022485 12a. Ohm's law states that the current passing through a conductor is directly proportional to the potential difference between the two points provided the other physical conditions remain constant (e.g. temperature) Note: last part about physical condition is impt

b. The graph is not a straight line passing through the origin but a curve.  Note: The graph passes thru origin ....

c.  When the potential difference increases, the resistance of the lamp increases. You need to make use of the graph!!

From the question "Using Fig.12.2, state and explain the change to the resistance of the lamp"

Note: Yun Xin, you need to state the changes in the gradient from the graph and link it to the resistance. Hence, as the potential difference increases, the gradient (1/R) of the graph decreases (become gentler). Hence, the value of R increases.

di. Rheostat 👌

ii. As V=IR, when the effective resistance increases as the rheostat's resistance increases, the potential difference would remain constant, so the current would decrease 👍

ei. 0.05A ✔

ii. 0.0125A ✔]]> 2021-07-29 11:25:47 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664022485 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664022521 metal as it is a good conductor of heat 👌]]> 2021-07-29 11:25:50 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664022521 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664023184 Rheostat 👍]]> 2021-07-29 11:27:09 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1664023184 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669871060 a. Ohm's law states that the current passing through a conductor between two points is directly proportional to the potential difference across the two points provided all other physical conditions (e.g. temperature) stays the same.

b. The graph is a curve and not a straight line👍

c. The resistance increases. This is because when the potential difference increases, the gradient, 1/R, decreases. Therefore, the resistance R increases 👍

di. A rheostat 👌

dii. Since V=RI, when component X is set to a higher resistance, the effective resistance will increase. Therefore, the current will decrease while the potential difference stays constant ✔

ei. 0.05A ✔

eii. 0.0125A ✔]]> 2021-08-05 09:45:02 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669871060 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669871427 The voltage across a conductor is directly proportional to the current that flows through it provided all other physical conditions stay the same (e.g. temperature) 👌]]> 2021-08-05 09:45:55 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669871427 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669871447 X can be set to a higher resistance. this will increase the total effective resistance. Since V=RI, with the current and voltage remaining the same, the current will decrease. 👌

(note: how can voltage stay the same and decrease at the same time)]]> 2021-08-05 09:45:58 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669871447 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669871877 The graph is not a straight line✔ and does not pass through the origin

Note - The graph does pass thru origin. Just the gradient is not constant i.e. graph is a curve. Hence, the filament lamp does NOT obey Ohm's Law

]]> 2021-08-05 09:46:56 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669871877 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669872635 0.05A 👌
12eii)
0.0125 A ✔]]> 2021-08-05 09:48:27 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669872635 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669873174 As the potential difference increases, the resistance increases.

Using Fig.12.2, state and explain the change to the resistance of the lamp

Note: Megan, you need to state the changes in the gradient from the graph and link it to the resistance. Hence, as the potential difference increases, the gradient (1/R) of the graph decreases (become gentler). Hence, the value of R increases.


]]> 2021-08-05 09:49:39 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669873174 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669874733 Rheostat ✔
When the resistance of the rheostat increases and the voltage stays the same, since V=IR, the current will decrease 👍

]]> 2021-08-05 09:52:53 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669874733 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669877022 0.05 A ✔
0.0125 A ✔]]> 2021-08-05 09:56:59 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669877022 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669877512 Flows ABCD ❌ DCBA
By using flemings left hand rule, the index finger represents the direction of the magnetic field which is pointed to the left, north pole to south pole👍 . the thumb which represents  the direction of the induced force points downwards on the side AB👍 and upwards on the side of DC. The middle finger which represents the direction of current points out of the paper (B to A) for the right side of the coil and (D to C) on the left side of the coil. thus the current flows ABCD? DCBA]]> 2021-08-05 09:57:51 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669877512 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669878868 X is a split ring commutator 👍 that helps reverse direction of current every half revolution allowing a continuous upward force on the left side and a continuous downward force on the right side of the coil ensuring the coil rotates continuously in the same clockwise direction.]]> 2021-08-05 10:00:51 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669878868 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669879407 a. DCBA. 👌 Using Fleming's left hand rule, the thumb points in the direction of the force, the second index finger points to the direction of the magnetic field (to the left) and the middle finger points to the current. ✔ Since the coil rotates clockwise and the magnetic current❓❓  travels from the north to the south pole, the current flows into the paper.  To generate an upward force, current must flow from D to C on the left side of the coil and B to A on the right side of trhe coil to generate a downward force on the right side of the coil. Therefore, the current flows DCBA.

c. Component X is a split ring commutator. 👌 When the switch is on, the current flowing through the coil and the magnetic forces acting on it causes the coil to turn clockwise. These forces makes the coil rotate until it reaches a vertical position. Although the current is cut off at this point as the coil is not longer in contact with the commutator, momentum carries it slightly beyond the vertical position and the coil comes in contact with the commutator again. reverses the direction of current every 1/2 revolution (when the coil is in a vertical position)  such that a continuous upwards force on the left side of the coil and a continuous downward force on the right side allowing the coil to complete full rotation. Thus it maintains its clockwise rotation.

Note: Your answer in 12C should answer the question "Why does the split ring commutator continue to rotate despite having no contact with the carbon brushes when the coil is vertical? 

 When the switch is on, the current flowing through the coil and the magnetic forces acting on it causes the coil to turn clockwise. These forces makes the coil rotate until it reaches a vertical position. Although the current is cut off at this point as the coil is not longer in contact with the commutator, momentum carries it slightly beyond the vertical position and the coil comes in contact with the commutator again.


d. The battery has been flipped to switch the positions of the positive and negative terminals. A stronger battery may have also been used. 👌]]> 2021-08-05 10:02:08 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669879407 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669879506 positively charged. 👍]]> 2021-08-05 10:02:22 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669879506 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669880133 Gravitational pull ✔]]> 2021-08-05 10:03:52 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669880133 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669880223 a. The current flows from DCBA👍. Using Fleming's Left-Hand Rule, the index finger which represents the direction of the magnetic field points towards the right LEFT, and the thumb which represents the direction of the induced force at DC points upwards, while the directions of the induced force at BA points downwards.✔ As the coil rotates clockwise, the middle finger representing the direction of current should point from DC at the plane of DC and to BA at the plane of BA, therefore, the direction of current is DCBA 👌

c. It is a split ring commutator.👌 A split ring commutator changes the direction of current from clockwise to anti-clockwise and vice versa every half a revolution when the coil is vertical . This ensures that the induced force on the plane of DC left side of the coil is always acting upwards and the induced force on the plane of BA right side of the coil is always acting downwards so that the coil only rotates clockwise continuously

d. The polarities of the battery is switched and a stronger battery is used ✔✔]]> 2021-08-05 10:04:05 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669880223 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669880741 Electrons from earth will flow into the sphere and neutralize the positive charges in the sphere making the sphere electrically neutral. 👍]]> 2021-08-05 10:05:18 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669880741 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669881896 The sphere will now move towards the the positively charged plate due to attraction. Unlike chargers attract. the sphere now has negative charges which are attracted to the positive charges in the positively charged plate hence is attracted towards it. 👍👍]]> 2021-08-05 10:07:25 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669881896 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669882597 Negative charges spread evenly in the sphere. 👌]]> 2021-08-05 10:09:00 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669882597 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669886174 ai. Positively charged ✔

aiii. Gravitational force 👌

bi. Negative charges will move from the earth to the sphere 👍

bii. The sphere will move towards the positively charged plate. This is because the sphere is now negatively charged and opposite charges attract. 👍👍

biii. The negative charges are spread out evenly in the sphere 👌]]> 2021-08-05 10:16:43 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669886174 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669887128 ai. Positively-charged 👍

ii. Gravitational force by the earth on the sphere ✔

bi. Electrons from the Earth will be attracted up to the sphere and neutralises the positive charges on the sphere making the sphere neutral 👌

ii. The sphere moves towards the positively charged plate. As unlike charges attract, the sphere which is neutral ❌negatively charged due to the removal of the earth would be attracted by the plate since unlike charges attract.

iii. The negative charges will spread out evenly on the surface on the sphere 👌👌]]> 2021-08-05 10:18:33 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669887128 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669889423 13(c) The split ring commutator reverses the direction of the current in the coil every half of a revolution when the coil is in vertical position so that the coil can continue to turn in one direction and complete the revolution.

13(d) The battery's terminals are reversed and a stronger magnet is used ]]> 2021-08-05 10:23:20 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669889423 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669890914 A i. positively charged 👌
ii. gravitational pull ✔
B i. electrons will flow up to the sphere from the earth because they are attracted to the positive charges in the sphere, thus neutralising the sphere 👍
ii. as unlike charges attract, the neutral❌ negatively charged sphere will move towards the positively charged plate since unlike charges attract
iii. the negative charges will spread out evenly on the surface of the sphere ✔]]> 2021-08-05 10:27:02 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669890914 https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669900561 clockwise. on AB the force is acting upwards and on DC the force acts downwards. the magnetic field acts towards the right. according to flemings left hand rule the current flow and the magnetic field are perpendicular to the induced force. thus the current flows from DCBA. ]]> 2021-08-05 10:47:50 UTC https://padlet.com/gregorywong_sg/5o1rc75ljkus27gz/wish/1669900561