Question

Two lenses of power +12 dioptre and -2 diopre are placed in contact. The focal length of the combination is given by:

(a) 8.33 cm
(b) 12.5 cm
(c) 16.6 cm
(d) 10 cm

Answer 1

Answer:10cm

Explanation:

P=p1+p2

One dioptre= 1 m^-1

P=+12-2

=10 m^-1

f=1/P

=1/(10 m^-1)

=0.1m

=10cm