Question

The sun subtends an angle of $(1/2{)}^o$ at earth.The image of the sun is obtained on a screen using a converging lens of focal length 1.5 cm.The diameter of the image will be :

• A. 0.13 mm
• B. 0.9 mm
• C. 1.8 mm
• D. 0.6 mm

Answer 1

The correct option is A 0.13 mm

If D be the diameter of image, then by geometrical considerations,
$D=$$f\times \theta$ where $\theta$ is in radians.

Hence, $D=1.5$$\times \frac{1}{2}\times \frac{\pi }{180}$

This comes out to be, $D=0.013cm$