Question

6. An object 5 cm high is placed at a distance 60 cm
in front of a concave mirror of focal length 10 cm.
Find (i) the position and (ii) size, of the image.
Ans. (i) 12 cm in front of the mirror, (ii) 1 cm

Answer 1

Hey!!Mate

Here is your ans:-

Explanation:

(i) Position of image is 12 cm in front of mirror. (ii) Size of image is -1 cm.

Solution

Here we have :-

● Height of object (h_0) = 5 cm.

● Distance of object (u) = -60 cm.

● Focal length (f) = -10 cm.

We will use mirror formula :-

● 1/f = 1/v + 1/u

⇒ 1/-10 = 1/v + 1/(-60)

⇒ 1/-10 = 1/v - 1/60

⇒ 1/v = 1/60 - 1/10

⇒ 1/v = (1 - 6)/60

⇒ 1/v = -5/60

⇒ 1/v = -1/12

⇒ -v = 12

⇒ v = -12 cm

So, position of image is 12 cm in front of mirror.

Now we will use magnification formula :-

● m = h_i/h_o = -v/u

⇒ h_i/5 = -(-12)/-60

⇒ h_i/5 = 12/-60

⇒ h_i/5 = 1/-5

⇒ -5h_i = 5

⇒ h_i = 5/-5

⇒ h_i = -1 cm

So, size of image is -1 cm.

I hope this will help you❤️❤️