Question

A burning candle and a screen are placed 40 cm apart when a spherical mirror is placed exactly in the middle of the two a sharp image of the candle flame is obtained on the screen. Find the nature and power of the lens

Answer 1

Explanation:

Object distance, u = -40cm

Image distance, v = 40 cm

Using lens formula,

1/f=1/v-1/u=1/40-1(-40) or

Focal length,

f=+20cm

The positive sign of focal length shows that it is a convex lens.

Now,

Magnification,

m = v/u= 40/(-40)= -1

Thus,

the image is real, inverted and same size as object.

Answer 2

The image of a candle flame at a distance of 40 cm from a spherical lens is formed on a screen placed on the other side of ... Identify the type of lens and write its focal length