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The angle of prism is A and one of its refracting surface is silvered. Light rays falling at an angle of incidence 2A on the first surface return back through the same path after suffering reflection at the silvered surface. The refractive index of the material of the prism is
The refractive index is calculated using the condition for the light to retrace its path after reflection.
The rays of different colours fail to converge at a point after passing through a thick converging lens. This defect is called
Chromatic aberration occurs due to the variation of refractive index with wavelength, causing different colors to focus at different points.
A transparent glass cube of length 24 cm has a small air bubble trapped inside. When seen normally through one surface from air outside, its apparent distance is 10 cm from the surface. When seen normally from opposite surface, its apparent distance is 6 cm. The distance of the air bubble from first surface is
The real distance is calculated using the apparent distances from both sides and the refractive index of glass.
Two lenses of power -15D and +5D are in contact with each other. The focal length of the combination is
The focal length of the combination is calculated using the sum of the powers of the individual lenses.
The size of the real image produced by a convex lens of focal length F is 'm' times the size of the object. The image distance from the lens is
The image distance is calculated using the magnification formula for convex lenses.
Converging or diverging ability of a lens or mirror is called
Focal power refers to the ability of a lens or mirror to converge or diverge light rays.
One of the necessary condition for total internal reflection to take place is (i = angle of incidence, i_c = critical angle)
Total internal reflection occurs when the angle of incidence is greater than the critical angle.
A beam of light is incident on a glass plate at an angle of 60°. The reflected ray is polarized. If angle of incidence is 45° then angle of refraction is (Given tan60°=√3, sin45°=1/√2)
The angle of refraction is calculated using Brewster's law and the given angle of incidence.
A spherical surface of radius of curvature 'R' separates air from glass of refractive index 1.5. The centre of curvature is in the glass. A point object P placed in air forms a real image Q in the glass. The line PQ cuts the surface at point 'O' and PO = OQ = x. Hence the distance 'x' is equal to
The distance is calculated using the mirror formula and the given conditions.
A ray of light is incident at an angle of incidence 'i' on one surface of prism of small angle A and emerges normally from the other surface. If the refractive index of the material of the prism is 'μ', then the angle of incidence is equal to
The angle of incidence is calculated using the small angle approximation and Snell's law.
A ray of light passes through an equilateral prism such that the angle of incidence (i) is equal to angle of emergence (e). The angle of emergence is equal to (3/4)th the angle of prism. The angle of deviation is
The angle of deviation is calculated using the given conditions and the properties of the prism.
A combination of two thin lenses in contact have power +10D. The power reduces to +6D when the lenses are 0.25 m apart. The power of individual lens is
The individual powers are calculated using the formula for combined power and the given separation.
The angle of deviation produced by a thin prism when placed in air is 'δ₁' and that when immersed in water is 'δ₂'. The refractive index of glass and water are 3/2 and 4/3 respectively. The ratio δ₁:δ₂ is
The ratio of deviations is calculated using the refractive indices of the prism in air and water.
A glass slab of thickness 4.5 cm is placed on the piece of paper on which an ink dot is marked. The refractive index of glass is 1.5. By how much distance would an ink dot appear to be raised?
The apparent raise is calculated using the formula for apparent depth.
For the same angle of incidence, the angle of refraction are 50°, 40°, 30° and 20° respectively in four different media A, B, C and D. The speed of light is maximum in medium
The speed of light is maximum in the medium with the smallest refractive index.
A convex lens of focal length 'f' in air has refractive index μ. When it is immersed in liquid of refractive index μ', its focal length becomes 'f' which is given by
The focal length in the liquid is calculated using the lensmaker's formula adjusted for the liquid's refractive index.
A ray of light incident at an angle i on one of the refracting face of prism emerges from the other face normally. If the angle of prism is 5° & the prism is made of a material of refractive index 1.5, then the angle of incidence is
The angle of incidence is calculated using the condition that the emergent ray is normal to the second face.
A biconvex lens has focal length (5/6) times the radius of curvature of either surface. The refractive index of the material of the lens is
The refractive index is calculated using the lensmaker's formula for a biconvex lens.
An object 5 cm tall is placed at 1 m from a concave spherical mirror which has a radius of curvature 20 cm. The size of the image is
The size of the image is calculated using the mirror formula and magnification.
A ray of light is incident normally on a glass slab of thickness 5 cm and refractive index 1.6. The time taken by a ray to travel from source to surface of slab is same as to travel through glass slab. The distance of source from the surface is
The distance is calculated using the time taken for light to travel in air and in the glass slab.
Some water is filled in a container of height 21 cm. What should be the height of water in the container, so that it appears half filled to the observer when viewed from the top of the container? [Refractive index of water = 4/3]
The height is calculated using the apparent depth formula.
Two thin lenses of focal lengths 'f₁' and 'f₂' are in contact and co-axial. The combination is equivalent to a single lens of power
The power of the combination is the sum of the powers of the individual lenses.
The equiconvex lens is made from glass of refractive index 1.5. If the radius of each surface is changed from 5 cm to 6 cm then the power
The power of the lens decreases as the radius of curvature increases.
The critical angle in the medium is 30°. The velocity of light in air V = 3 × 10⁸ m/s
The velocity of light in the medium is calculated using the critical angle and the velocity in air.
Which one of the following is not associated with the total internal reflection?
Dispersion of light is not related to total internal reflection.
Two thin convex lenses of focal lengths 20 cm and 25 cm are placed in contact with each other having common principal axis. The effective power of the combination is (D = diptor)
The effective power is calculated by summing the powers of the individual lenses.
An air bubble in a glass slab (μ = 1.5) is 6 cm deep as viewed from one face and 4 cm deep as viewed from the other face. The thickness of glass slab is
The thickness is calculated using the apparent depths from both sides and the refractive index.
Focal length of a convex lens will be minimum for
Violet light has the highest refractive index, resulting in the shortest focal length.
A ray of light passes through equilateral prism such that 2i = 2e = 5A/4, where i, e and A are angle of incidence, angle of emergence and angle of prism respectively. The angle of deviation is equal to
The angle of deviation is calculated using the given relationship between the angles.
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