Question

A concave mirror forms a real image of an object placed in front of it at a distance

30cm. The focal length of mirror is 15 cm.(a) where will be the image formed & (b)
what will be the length of image?​

Answer 1

u=−30cm and magnification m=(−v/u)=−3 so v=(3u)

image is real so m should be negative v should be negative so v=−90cm

putting the above values of v and u in the Mirror equation,

1/f=1/u +1/v

we get focal length f=−22.5cm and image position v=−90cm