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10 (a) (i) Which lens is a converging lens with the greatest power? A B C D (ii) The equation that relates the power of a lens to the focal length of the lens is power (in dioptres) = 1 / focal length (in metres) The power of a lens is 5 dioptres - Edexcel - GCSE Physics - Question 10 - 2019 - Paper 1
Question 10
10 (a) (i) Which lens is a converging lens with the greatest power? A B C D (ii) The equation that relates the power of a lens to the focal length of the l... show full transcript
Worked Solution & Example Answer:10 (a) (i) Which lens is a converging lens with the greatest power? A B C D (ii) The equation that relates the power of a lens to the focal length of the lens is power (in dioptres) = 1 / focal length (in metres) The power of a lens is 5 dioptres - Edexcel - GCSE Physics - Question 10 - 2019 - Paper 1
Step 1
Which lens is a converging lens with the greatest power?
Answer
To determine which lens is a converging lens with the greatest power, we need to look at the curvature of each lens illustrated in options A, B, C, and D. A converging lens is typically thicker in the middle and thinner at the edges. The lens that is most convex (bulging outwards) will have the greatest power. After analyzing the shapes:
- Lens A has a moderate curvature.
- Lens B appears to be more convex than A.
- Lens C is less convex and has a flatter design.
- Lens D, though there, does not display a strong converging profile.
Therefore, lens B is the correct answer as it is the most converging.
Step 2
Use the equation to calculate the focal length of the lens in cm.
Answer
To find the focal length of the lens, we use the formula provided:
P = rac{1}{f}
Where:
- P is the power in dioptres,
- f is the focal length in meters.
Given that the power P is 5 dioptres:
f = rac{1}{P} = rac{1}{5} = 0.2 ext{ meters}
To convert this into centimeters, we multiply by 100:
Thus, the focal length of the lens is 20 cm.