We have learned that silver smooth reflective surface is a poor absorber, poor emitter or a good reflector of infra-red radiation.
How can we apply this concept to this suitation?
2022PPp1q17
Answer: Option D
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Dull black is the best absorber and best emitter of infra-red radiation.
When we are outdoor under the sun, ideally we should wear light colours shirt like white or yellow, so that we wont feel so hot.
2019PPP1Q33 Ans: Option B
2007PPP1Q28 Ans: Option B
Torch lamp or bulb is a non-ohmic conductor. The V-I graph has an increasing gradient indicating resistance increases. As the current through the filament of bulb increases (due to p.d across increases), temperature increases and resistance increases.
For an ohmic conductor, the graph of V against I is a straight line with constant gradient and passes through the origin.
Something to thing about:
What if there is an option E whereV increases from 0, 1, 2, 3I increases from 0, 6, 10, 12 respectively. The graph will be a typical ohmic graph, similar shape to option B, but will you choose E?
Refer to the last section of the video from 4:37 s.
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