Question

Focal length of a concave mirror is 20 cm find the position of the image of the object is kept at 10 cm in front of the mirror

Answer 1

Answer:

10cm

Explanation:

Focal length= -20cm (-ve sign because it is measured opposite to direction of incident ray)

Object distance u=-10cm(-ve sign because it is measured opposite to direction of incident ray)

1/f=1/u+1/v

1/-20 = 1/-10 +1/v

v=10cm(real and inverted image is formed)