A tree has a height of 360 cm and is placed in front of a co

A tree has a height of 3.60 cm and is placed in front of a concave mirror. The image of the tree is inverted, 1.30 cm tall, and located 12.5 cm in front of the mirror. Find the focal length of the mirror. answer in cm

Solution

According to the given problem,

A concave mirror has a real focal length +f, image distance v = 12.5cm

First, find the object distance using magnification,

M = v/u = 1.3cm / 3.6cm = 0.361

u = v/M = 12.5cm / 0.61

u = 34.61cm

Applying .. 1/f = 1/v + 1/u

1/f = 1/12.5cm + 1/34.61cm

1/f = 0.1088

f = 9.183 cm