Question

an object of height 7 cm is kept at distance of 25 in the front of the concave mirror the focal length of the mirror is 15 CM at which distance from the mirror should a screen be kept so as to get a clear image what will be the sea and nature of the image

Answer 1

We have,

Object placed, distance (u) = -27 cm

A concave mirror of focal length (f) = -18 cm

 

We know, 1/f = 1/u + 1/v

or, 1/(-18) = 1/(-27) + 1/v

or, 1/v = 1/18 + 1/27

or, v = - 54 cm

Hence image formed at distance -54 cm

we know,

Magnification (m ) = - image distance (v)/ object distance(u) = Image height (h2)/ Object height (h1)

where, object height (h1) = 7 cm

Therefore,

- (54)/(-27) = Image height (h2)/7

or, Image height (h2) = - (54) x 7/(-27) =-14 cm

So, Image is formed on the same side as that of the object, since, negative sign indicated. The size of the image is 14 cm and inverted.

so it's help you