JEE Main & Advanced
Sample Paper
JEE Main Sample Paper-39
question_answer
Consider the following u-v diagram regarding the experiment to determine the focal length of a convex lens. At the point A, the values of u and v are equal. The focal length of the lens is
A) 40 cm
B) 20 cm
C) 10 cm
D) 15 cm
Correct Answer:
B
Solution :
Clearly the co-ordinates of A are (2f, 2f) \[\therefore \] \[f=\frac{40}{2}=20cm.\]