Question

An abject is placed 18cms away from a concave mirror whose focal length is 10cms .Then the size of area of the image if the object be 4mm broad and 12mm long is ______

Answer 1

The image formed by the concave mirror will have a size of 4 mm broad and 4 mm long.

Step-by-step explanation:

To determine the size of the image formed by a concave mirror, we can use the mirror formula: 1/f = 1/v - 1/u, where f is the focal length, v is the image distance, and u is the object distance. First, let's calculate the image distance:

u = -18 cm (because the object is placed 18 cm in front of the mirror)
f = 10 cm (given focal length)
Using the mirror formula: 1/10 = 1/v - 1/-18

This gives us the image distance v = -6 cm. Since the image distance is negative, the image formed is virtual and located behind the mirror. Now, let's calculate the magnification:

Magnification (m) = -v/u = -(-6)/(-18) = 1/3

The height of the image is determined by the magnification:

Height of the image = Magnification x Height of the object = (1/3) x 12 mm = 4 mm

So, the size of the area of the image is 4 mm broad and 4 mm long.

Learn more about concave mirror