Question

The magnification produced by concave mirror is three times the size of the object . This image is obtained on the screen three distance Between the Lens and Image is 80cm at what distance should the candle be placed from the lens?

Answer 1

Answer:

As the image is obtained on the screen , it is real .

so,

Magnification , m = –3 ,

v = 80 cm

u = ?

As m = v/u

so,

–3 = 80/u,

u = –80/3 cm .

From

1/f = 1/v - 1/u

=1/80 + 3/80

= 4/80

= 1/20

1/f = 1/20cm

so,

f = 20 cm .

Explanation: