4 (a) (i) Figure 4 shows two light rays hitting a glass lens - Edexcel - GCSE Physics - Question 4 - 2020 - Paper 1
Question 4
4 (a) (i) Figure 4 shows two light rays hitting a glass lens. On Figure 4, draw the two light rays after they leave this lens.
(ii) Figure 5 shows two light rays ... show full transcript
Worked Solution & Example Answer:4 (a) (i) Figure 4 shows two light rays hitting a glass lens - Edexcel - GCSE Physics - Question 4 - 2020 - Paper 1
Step 1
Draw the two light rays after they leave this lens.
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Answer
The rays emitted from the lens should be drawn as converging rays that converge at a focal point on the right side of the lens.
Step 2
Draw the two light rays after they leave this lens.
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Answer
The rays should be shown diverging after passing through the lens, indicating that they are spreading away from a virtual focal point.
Step 3
Calculate the power of the lens.
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Answer
The focal length is given as 25 cm, which needs to be converted to meters for calculation. Thus, we have:
f=0.25 m
Using the power formula:
P=f1=0.251=4 dioptres
Step 4
Use the graph in Figure 7 to determine the time when P and Q were at the same temperature.
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Answer
The intersection point of the graphs of P and Q indicates the time at which they are at the same temperature. By reading the graph, identify the time, which falls in the range of 11 to 13 minutes.
