Question

The focal length of a concave mirror is 50cm where an object be placed so tht it's image is two times and inverted

Answer 1

So, we know that

m = -v/u

So, m = -2 ( as the image is inverted and real )

Then,

-2 = -v/u

-2u = -v

2u = v

So mirror formula is

1/f = 1/v+1/u

So substitute the value of v

So f = -50cm

1/-50 = 1/2u + 1/u

1/-50 = 1+2/2u

1/-50 = 3/2u

2u = -150

u = -75cm

So the object should be placed -75cm from the lens to get the conditions specified in the question. Hope you will understand:)