Question

if the focal length is 5cm and image distance is 2.5cm in a convex mirror find its object distance​

Answer 1

Answer:

Object distance is 5cm.

Explanation:

f = 5

v = 2.5

1/f = 1/v + 1/u

1/u = 1/v - 1/f

1/u = 1/2.5 - 1/5

1/u = 10/25 - 1/5

1/u = 10-5/25

1/u = 5/25

1/u = 1/5

u = -5 cm

Answer 2

$f = 5cm \\ v = 2.5cm \\ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \\ \frac{1}{5} = \frac{ 1 \times 10}{2.5 \times 10} + \frac{1}{u } = \frac{10}{25} + \frac{1}{u}$

$- \frac { 1}{u} = \frac{10}{25} - \frac{1}{5} = \frac{10 - 5}{25} = \frac{5}{25} = \frac{1}{5}$

$- \frac{1}{u} = \frac{ 1}{5} \\ - u = 5\\ u = object \: distance = - 5cm$