A lens which converges a beam of parallel rays to a point is called______________? April 17, 2025 by admin A. diverging (or concave) lens B. converging (or convex) lens C. plano concave lens D. plano convex lens
The diameter of a lens is called________________? April 17, 2025 by admin A. focal length B. principal axis C. aperture D. radius of curvature
Unit of power of a lens is________________? April 17, 2025 by admin A. meter B. watt C. diopter D. horsepower
The power of a concave lens is_______________? April 17, 2025 by admin A. real B. virtual C. positive D. negative
If an object is placed away from 2f of a converging lens then the image will be_______________? April 17, 2025 by admin A. real and erect B. virtual and erect C. real and inverted D. virtual
Magnifying power of simple microscope______________? April 17, 2025 by admin A. increase with increase in focal length B. increase with decrease in focal length C. no effect with decrease or increase with focal length D. list distance of distinct vision
The least distance of distinct vision for a normal eye is_______________? April 17, 2025 by admin A. 15 cm B. 25 cm C. 30 cm D. 40 cm
If a convex lens of large aperture fails to converge the light rays incident on it to a single point, it is said to suffer from______________? April 17, 2025 by admin A. chromatic aberration B. spherical aberration C. both spherical and chromatic D. distortion
A convex lens of focal length f1 and a concave lens of focal length f2 are placed in contact. The focal length of the combination is_____________? April 17, 2025 by admin A. f2 + f1 B. f2 – f1 C. f1f2/f2+f1 D. f1f2/f1-f2
In multimode step index fibre the refractive index of core and cladding is____________? April 17, 2025 by admin A. same B. different C. zero D. different with refractive index of core higher than cladding
