Question

an object is placed at a distance of 36 cm from a concave mirror of focal length 12 cm find the image distance​

Answer 1

Step-by-step explanation:

Here,

Object distance u = - 36 cm

focal length f = - 12 cm

According to mirror formula : -

$\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$

$= > \frac{1}{v} + \frac{1}{ - 36} = \frac{1}{ - 12}$

$= > \frac{1}{v} = \frac{1}{36} - \frac{1}{12}$

$= > \frac{1}{v} = \frac{1 - 3}{36}$

$= > \frac{1}{v} = \frac{ - 2}{36}$

$= > \frac{1}{v} = \frac{1}{ - 18}$

$v = - 18 \: cm$

Therefore image is formed at 18 cm in front of the concave mirror.

Answer 2

Answer:

      v = -18cm

Explanation:

object distance - u = -36cm

focal length - f = -12cm

image distance - v

1 / v + 1 / u = 1 / f

1 / v = 1 / f - 1 / u

1 / v = u - f / uf

v = uf / u - f

v = -36 × -12 / -12 + 36

v = 36 × 12 / 24

v = 36 / 2

v = -18cm

Image is formed on the same side of the object