Question

The sun's diameter is $1.4\times {10}^{9}m$ and its distance from the earth is ${10}^{11}m.$ The diameter of its image, formed by a convex lens of focal length 2m will be

• A. 0.7 cm
• B. 1.4 cm
• C. 2.8 cm
• D. Zero (i.e. point image)

Answer 1

The correct option is C 2.8 cm

From figure $\frac{D}{d}=\frac{{10}^{11}}{2}\Rightarrow d=\frac{2\times 1.4\times {10}^9}{{10}^{11}}=2.8cm.$