Question

the focal length of a concave mirror is30 cm. An object of 30cm height is placed at its focus. Calculate the size and position of image.​

Answer 1

Answer:

0

Explanation:

Given:

The focal length of the concave mirror (f) = 30cm

Height of object at focus (h) = 30cm

Position of object (u) = 30cm

Position of image (v) =?

Height of image (h₁) =?

Now, using the mirror formula

1/f = 1/v + 1/u

⇒ 1/v = 1/f - 1/u

⇒ 1/v = -1/30 - (-1/30)

⇒ 1/v = -1/30 + 1/30

⇒ 1/v = 0cm

Now, using magnification formula

m= h₁/h and m= -v/u

⇒ h₁/h = -v/u

⇒ h₁/30 = - ( 0/ -30)

⇒ h₁ = 0 × 30

⇒ h₁ = 0cm

Since, if the object is placed on f then the image formed at infinite so 0 is the correct answer.