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A boy is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. The diameter of the Sun is 1.39 ×109 m and its mean distance from the earth is 1.5 × 1011 m. What is the diameter of the Sun’s image on the paper?
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- 9.2 × 10–4 m
- 6.5 × 10–4 m
- 6.5 × 10–5 m
- 12.4 × 10–4 m
Correct Option: A
| We have , |  |  | = | |||
| u | Size of object |
| or , Size of image = | | | × Size of object | |
| u |
| = |  |  | × (1.39 × 109) | |
| 1.5 × 1011 |
= 0.92 ×10–3 m = 9.2 × 10–4 m
∴ Diameter of the sun’s image = 9.2 × 10–4 m.
