A thin converging lens is used to focus the rays from the #Sun# on to the piece of paper. when the rays burn a hole on the paper, the distance between the lens and the paper is __________ the focal length of the lens. { options are;- } ??

A. less than half
B. equal to half
C. equal to
D. equal to twice

please do do do answer and explain it as well.

1 Answer
Jun 30, 2016

C. equal to

Explanation:

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In the figure above parallel rays from sun (infinity) after passing through the convex lens are focused to a point F. This point is the focal point.

Therefore, distance between the lens and the paper; where a hole is burnt due to concentration of light rays (heat rays in this instance); is equal to the focal length of the lens.