A small object is placed at distance of 3.6 cm from a magnifier of focal length 4.0 cm. a. find the position of theimage. B. find the linear magnification c. Find the angular magnification.

Options

A. 10
B. 7
C. 5
D. None of these

Answer

B

Explanation

If the object is placed at a distance `u_(0)` from the lens, the angel subtended by the object on the lens is `beta = (h)/(u_(0))` where h is the height of the object. The maximum angle subtended on the unaided eye is `alpha = (h)/(D)`
Thus, the angular magnification is
`m = (beta)/(alpha) = (D)/(u_(0)) = (25 cm)/(3.6 cm) = 7.0`