Convex lens has a focal length and concave lens has a focal length.

positive

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

negative

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

zero

No worries! We‘ve got your back. Try BYJU‘S free classes today!

inverse

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct options are
A positive
B negative

For convex lens, focus is on the opposite side to the incident light rays. The focus is called real focus and its focal length is positive.

For concave lens, focus is on the same side as the incident light rays. The focus is called virtual focus and its focal length is negative.

Suggest Corrections

Similar questions

Question 8
Which of the following statements is true?
(a) A convex lens has 4 dioptre power having a focal length 0.25 m.
(b) A convex lens has -4 dioptre power having a focal length -0.25 m.
(c) A concave lens has 4 dioptre power having a focal length 0.25 m.
(d) A concave lens has 4 dioptre power having a focal length -0.25 m.

Q. A combination of convex and concave lenses has power

4 D

.If the convex lens has power

5 D

focal length of the concave lense will be

Q. When a thin convex lens is put in contact with a thin concave lens of the same focal length, the resultant combination has focal length equal to :

If a lens has a focal length, f = -12 cm. then it is a

Q. An achromatic combination of concave and convex lens has power

5

D. If the power of convex lens is

4

D, then the magnitude of focal length of concave lens is?

Join BYJU'S Learning Program