Question

b) an object of height 10 cm is placed in front concave mirror of focal length 30 cm at a distance 90 cm .
FIND
I)POSITION OF IMAGE FORMED
II)HEIGHT OF THE IMAGE​

Answer 1

Height of object, h =10cm, object distance u=−90cm, focal length f=−30cm

Now, from mirror formula :

1/f=1/v+1/u

1/v=1/f-1/u

1/v= -1/30+1/90

1/v= -3+1/90

1/v= -1/45

v=−45cm - image distance

Magnification, m= −v/ u

= -(-45/-90)

= -1/2

Size of image, h¹ =m(h)

= -1/2*10

= -5