Question

A screen is held at a distance of 50cm in front of a concave mirror of focal length 20cm. At what range of distances should a candle flame be held from the mirror to obtain its real image on the screen?Immersive Reader

Answer 1

Answer:

(20-33.33)cm in front of the mirror

Explanation: My mate,

See there is only 1 case possible in Concave mirror to obtain a virtual image and that is between focus and pole of the mirror.

Since, we know that focus of the mirror is 20cm so any value beyond 20 cm will do the job. But in this case, we are given a screen, so according to the question we will find the maximum limit of the object distance(u) with the help of screen distance(v).

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

=> $\frac{-1}{50} + \frac{1}{u} = \frac{-1}{20}$

=> $\frac{1}{u}=\frac{-1}{20} +\frac{1}{50\\}$

=> $\frac{1}{u}=\frac{-5+2}{100}$

=> $\frac{1}{u} =\frac{-3}{100}$

=> u = (-33.33)cm

Hope you understand!!!!

Please mark me the Brainiest !!!!

Answer 2

Answer:

The focal length of concave mirror ia negative

So f =-20 cm

u=-50cm

we know that

1/f=1/u+1/v

-1/20=-1/50+1/v

1/v= 1/50-1/20

1/v = 20-50/1000

1/v=-30/1000

v=-33.33cm

The real image is erect