Geometrical Optics - Optics - Physics Previous Year Questions

What will be the minimum angle of incidence such that the total internal reflection occurs on both the surfaces?

Two identical prisms of refractive index \(\sqrt{3}\) are kept as shown in the figure. A light ray strikes the first prism at face AB. Find

(A) the angle of incidence so that the emergent ray from the first prism has minimum deviation;

(B) through what angle, the prism DCE should be rotated about C so that the final emergent ray also has minimum deviation?

A point object is placed at a distance of 20 cm from a thin plano-convex lens of focal length 15 cm , if the plane surface is silvered. The image will form at

A simple telescope used to view distant objects has eyepiece and objective lens of focal lengths $f_e$ and $f_0$, respectively. Match Column I with Column II:

A biconvex lens of focal length $f$ forms a circular image of sun of radius $r$ in focal plane. Then

Graph of position of image versus position of point object from a convex lens is shown. Then, the focal length of the lens is

A ray of light travelling in water in incident on its surface open to air. The angle of incidence is \(\theta\), which is less than the critical angle. Then there will be

Statement 1 :

The formula connecting u, v and f for a spherical mirror is valid only for mirrors whose sizes are very small compared to their radii of curvature.

Statement 2 :

Laws of reflection are strictly valid for plane surfaces, but not for large spherical surfaces.

In an experiment to determine the focal length (f) of a concave mirror by the u-v method, a student places the object pin A on the principal axis at a distance x form the pole P. The student looks at the pin and its inverted image form a distance keeping his/her eye in line with PA. When the student shifts his/her eye towards left, the image appears to the right, oh the object pin. Then,

Light travels as a

The phases of the light wave at \(c, d, e\) and \(f\) are \(\phi_c, \phi_d, \phi_{e}\) and \(\phi_{f}\) respectively.

It is given that \(\phi_{c} \neq \phi_{f}\).

Two beams of red and violet colours are made to pass separately through a prism (angle of the prism is 60\(^\circ\)). In the position of minimum deviation, the angle of refraction will be :

A light beam is travelling from Region I to Region IV (Refer figure). The refractive index in Regions I, II, III and IV are \({n_0},{{{n_0}} \over 2},{{{n_0}} \over 6}\) and \({{{n_0}} \over 8}\), respectively. The angle of incidence \(\theta\) for which the beam just misses entering Region IV is

An optical component and an object S placed along its optic axis are given in Column I. The distance between the object and the component can be varied. The properties of images are given in Column II. Match all the properties of images from Column II with the appropriate components given in Column I. Indicate your answer by darkening the appropriate bubbles of the 4 \(\times\) 4 matrix given in the ORS.

	Column I		Column II
(A)		(P)	Real Image
(B)		(Q)	Virtual Image
(C)		(R)	Magnified Image
(D)		(S)	Image at infinity

A student performed the experiment of determination of focal length of a concave mirror by \(u\)-\(v\) method using an optical bench of length 1.5 m. The focal length of the mirror used is 24 cm. The maximum error in the location of the image can be 0.2 cm. The 5 sets of (\(u,v\)) values recorded by the student (in cm) are : (42, 56), (48, 48), (60, 40), (66, 33), (78, 39). The data set(s) that cannot come from experiment and is (are) incorrectly recorded, is (are)

A ball is dropped from a height of 20 m above the surface of water in a lake. The refractive index of water is 4/3. A fish inside the lake, in the line of fall of the ball, is looking at the ball. At an instant, when the ball is 12.8 m above the water surface, the fish sees the speed of ball as (Take g = 10 m/s\(^2\))

The focal length of a thin biconvex lens is 20 cm. When an object is moved from a distance of 25 cm in front of it to 50 cm, the magnification of its image changes from m₂₅ to m₅₀. The ratio \({{{m_{25}}} \over {{m_{50}}}}\) is __________.

A ray OP of monochromatic light is incident on the face AB of prism ABCD near vertex B at an incident angle of 60\(^\circ\) (see figure). If the refractive index of the material of the prism is \(\sqrt3\), which of the following is(are) correct?

A large glass slab (\(\mu\) = 5/3) of thickness 8 cm is placed over a point source of light on a plane surface. It is seen that light emerges out of the top surface of the slab from a circular area of radius R cm. What is the value of R?

Image of an object approaching a convex mirror of radius of curvature 20 m along its optical axis is observed to move from \({{25} \over 3}\) m to \({{50} \over 7}\) m in 30 s. What is the speed of the object in km per hour?