Refraction at Spherical Surfaces & Lens Maker — Practice Questions
Free NEET Physics multiple-choice questions on Refraction at Spherical Surfaces & Lens Maker. Attempt each question and reveal the answer with a full explanation.
A biconvex lens has a radius of curvature of 20 cm for each surface. If the refractive index of the material of the lens is 1.5, the power of the lens is: +5 D +10 D -5 D -10 D The focal length of a lens of refractive index 1.5 is f . If it is replaced by another lens of same geometry but refractive index 1.6, its focal length will: Decrease Increase Remain same Become infinite The chromatic aberration in lenses is caused by: Variation of refractive index with wavelength Spherical shape of the lens Reflection from the lens surface Interference of light The refractive index of the material of a prism is (A/2) , where A is the angle of prism. The angle of minimum deviation is: 180 - 2A 180 - A 90 - A A/2 A biconvex lens of focal length f is formed of a material of refractive index 1.5 . If it is immersed in a liquid of refractive index 2.0 , its focal length and nature will be: -2f , concave 2f , convex -f , concave f , convex The focal length of a glass lens ( g = 1.5 ) in air is 20 cm . What is its focal length in water ( w = 1.33 )? 80 cm 40 cm 20 cm 10 cm An astronomical telescope has an objective and eyepiece of focal lengths 40 cm and 4 cm respectively. To view an object 200 cm away from the objective, the lenses must be separated by a distance: 54 cm 46 cm 50 cm 37.3 cm The focal length of a convex lens of refractive index 1.5 is f in air. When it is immersed in a liquid of refractive index 4/3 , its focal length will become: 4f 2f f/2 f/4 A convex lens and a concave mirror are placed 20 cm apart. An object is placed 15 cm in front of the convex lens (focal length 10 cm ). If the final image is formed at the object itself, what is the focal length of the concave mirror? 5 cm 10 cm 20 cm 15 cm A point object is placed at a distance of 60 cm from a convex lens of focal length 30 cm . If a plane mirror is put perpendicular to the principal axis of the lens at a distance of 40 cm from it, the final image would be formed at a distance of: 20 cm from the plane mirror, virtual 20 cm from the lens, real 30 cm from the lens, real 60 cm from the lens, real In a displacement method, the distances between the two positions of a convex lens for which a sharp image of an object is formed on a screen is d . If the distance between the object and the screen is D , then the focal length f of the lens is: D 2 - d 2 4D D 2 + d 2 4D D-d 4 D+d 4 In the displacement method, the heights of the images in the two positions of the lens are h 1 and h 2 . The height of the object h is given by: h 1 h 2 (h 1 + h 2)/2 h 1 2 + h 2 2 h 1 h 2 / (h 1 + h 2) A plano-convex lens of refractive index 1.5 and radius of curvature 20 cm is silvered at the plane surface. The focal length of the system is: 20 cm 40 cm 10 cm 5 cm The focal length of a plano-convex lens of refractive index 1.5 and radius of curvature 30 cm is: 60 cm 30 cm 15 cm 90 cm The power of a thin convex lens ( = 1.5 ) is 5 D . When it is placed in a liquid of refractive index n = 1.5 , its power will be: 0 D 5 D 2.5 D Infinite If a convex lens of focal length f is cut into two identical halves along the principal axis, the focal length of each part will be: f f/2 2f Infinite A microscope is focused on a mark on a table and then a glass slab of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again? 1 cm upward 1 cm downward 2 cm upward 4.5 cm upward A thin equiconvex lens of focal length 10 cm and refractive index 1.5 is cut into two equal halves by a vertical plane passing through the principal axis. The focal length of each half is: 10 cm 20 cm 5 cm Infinite The focal length of a convex lens is M . If the lens is cut into two pieces along a plane perpendicular to the principal axis, the focal length of each piece will be: 2M M/2 M Infinite The minimum distance between an object and its real image formed by a convex lens of focal length f is: 4f 2f f 3f