An object is kept 40 cm in front of a concave mirror of focal length of 20 cm. Find the position and nature of the image. Draw a ray diagram to show the formation of image in this case.

Explanation

Concave mirror
u = -40 cm , f= -20 cm , v = ? Nature = ?
According to mirror formula
` 1/v + 1/u = 1/f Rightarrow 1/v + 1/(-40) = 1/(-20)`
` Rightarrow 1/v - 1/40 = (-1)/20`
` Rightarrow 1/v = (-1)/20 + 1/40 = ( -2+1)/40 = (-1)/40`
v = -40 cm
Position : Image is formed 40 cm in front of the concave mirror.
Nature : Image is real and inverted .