Question

a converging lens has a focal length of 15 cm and object is placed 60 cm from the lens determine the image distance

Answer 1

Focal length , f = 15 cm
Object distance , u = - 60 cm
Image distance, v = v

Lens formula
1/v - 1/u = 1/f

1/v - (1/-60) = 1/15
1/v +1/60 = 1/15
1/v = 1/15-1/60
1/v = ( 4 -1)/60
1/v = 3/60
V = 20 cm

Answer 2

MINE IS CORRECT, THE OTHER ONE HAS ERROR

Focal length , f = 15 cm

 Object distance , u = - 60 cm

 Image distance, v = ?

 Lens formula 1/v - 1/u = 1/f

1/v - (1/-60) = 1/15

1/v +1/60 = 1/15

1/v = 1/15-1/60

 1/v = ( 4 -1)/60

1/v = 3/60

 V = 20 cm

behind the mirror, erect, virtual