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Wonders of Physics

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2016 Pure Physics P1 Q40 – Voltage and Power of Bulb Y when X is switched off

2016 PPp1q40

Solutions: Option C
[There is another similar question in 2013 Nov Pure Physics P1Q40. The answer is Option C too. Refer to the last section of this post]

Refer to the 2 videos below. The 1st one is faster if you know that the bigger the resistance, by proportion, the bigger the potential difference of the component as it will take a larger portion of the emf wrt to the other components in series. This method is especially useful for MCQ.

If you are still unsure, you may put in values to find the I, V and P across the components. This will be more tedious and time-consuming.

Another similar question is 2013 Nov Pure Physics P1 Q40.

2013 PP p1q40

Solutions: Option C


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Identifying what lens, focal length and image from 2 rays – PP2010P1Q23 and SP2014P1Q11

These 2 questions are actually the same. Q23 is from 2010 Pure Physics P1 while Q11 is from 2014 Sci Physics P1. Take a look at these 2 questions. If you are not sure, view the video below for the explanation.

Capture1 PP 2010

Answer to Q23: Option A

Capture2 2014SP

Answer to Q11: Option D

If you do not know how to answer these 2 questions, view this video and also refer to the lens summary below.