Q

A lens has power -5 D. What is its focal length?

RRB Group-D 30/08/2022 / Shift-II 2022
✓ Answer: B -20 cm
f = 1/(-5) m = -20 cm.
← Previous Question Next Question →

📚 Related Questions — Light

1 What can divide sunlight into its constituent colours? 2 Why is white light dispersed by a prism? 3 Which instrument uses the principle of refraction? 4 A ray in air strikes a medium of refractive index √2 at… 5 The magnification produced by a lens is related to object distance u… 6 What does a negative magnification indicate for a spherical mirror?