Ray Optics and Optical Instruments - Result Question 37

37. A boy is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10cm. The diameter of the Sun is 1.39×109m and its mean distance from the earth is 1.5×1011m. What is the diameter of the Sun’s image on the paper?

(a) 9.2×104m

(b) 6.5×104m

(c) 6.5×105m

(d) 12.4×104m

[2008]

Show Answer

Answer:

Correct Answer: 37. (a)

Solution:

  1. (a) We have, |vu|= Size of image  Size of object 

or, Size of image =|vu|, Size of object

=(1011.5×1011)×(1.39×109) =0.92×103m=9.2×104m

Diameter of the sun’s image =9.2×104m.



NCERT Chapter Video Solution

Dual Pane