Question

In the setup shown below, a clear image of a distant object is obtained on the screen. The local lens
the concave mirror is:

a) 11.4 cm
b)9.4
c) 9.8 cm
d) 9.9 cm​

Answer 1

Given that,

The setup shown below a clear image of a distant object is obtained on the screen.

Focal length :  

Focal length is the distance between the center of mirror and focus.

We need to calculate the focal length of the concave mirror

If object is at infinity its image will formed at focus because it is concave mirror.

Here object is at 11.8 cm mark of scale and screen at 2 cm mark of scale. Since image is formed at focus

$f=11.8-2=9.8\ cm$

Hence, Focal length is 9.8 cm.

(c) is correct option

Learn more :

Topic : optics

https://brainly.in/question/2013969

Answer 2

Explanation:

f= 11.8- 2 = 9.8cm

therefore the answer is 9.8 cm