In the case of the displacement method of lenses, the product of magnification in both cases is:

In the displacement method, a convex lens is placed in between an object and a screen. If the magnifications in the two positions are m₁ and m₂ and the displacement of the lens between the two positions is x, then the focal length of the lens is:

The focal length of a planoconvex glass lens is 20 cm $\left({\mu }_0=1.5\right)$. The plane face of it is silvered. An illuminating object is placed at a distance of 60 cm from the lens on its axis along the convex side. Then the distance (in cm) of the image is:

Two thin similar convex glass surfaces are joined together front to front with its rear portion silvered such that a sharp image of an object at infinity is formed 20 cm from the mirror. When the air between the glass pieces is replaced by water $\left({\mathrm{\mu }}_{\mathrm{w}}=4/3\right)$, then the image formed from the mirror is at a distance of: (Thickness of lens is negligible.)

A convex lens of focal length 100 cm and a concave lens of focal length 10 cm are placed coaxially at a separation of 90 cm. If a parallel beam of light is incident on the convex lens, then after passing through the two lenses, the beam:

Yellow light is refracted through a prism producing minimum deviation. If i₁ and i₂ denote the angle of incidence and the angle of emergence for the prism respectively, then:

At what angle will a ray of light be incident on one face of an equilateral prism, so that the emergent ray may graze the second surface of the prism $(\mu =2)$?

A prism of the refractive index $\sqrt{2}$ has a refracting angle of 60^o. At what angle must a ray be incident on, so that it suffers a minimum deviation?

An astronomical telescope has an objective of focal length 100 cm and an eyepiece of focal length 5 cm. The final image of a star is seen 25 cm from the eyepiece. The magnifying power of the telescope is:

When a telescope is adjusted for normal vision, the distance of the objective from the eye-piece is found to be 80 cm. The magnifying power of the telescope is 19. What are the focal lengths of the lenses?

The focal lengths of the objective and eye lens of a telescope are respectively 200 cm and 5 cm. The maximum magnifying power of the telescope will be

A ray of light incident at an angle $\mathrm{\theta }$ on a refracting face of a prism emerges from the other face normally. If the angle of the prism is 5$°$ and the prism is made of a material of refractive index 1.5, the angle of incidence is:

A short pulse of white light is incident from air to glass slab at normal incidence. After travelling through the slab, the first colour to emerge is:

An object approaches a convergent lens from the left of the lens with a uniform speed of 5 m/s and stops at the focus. The image

A passenger in an aeroplane shall:

You are given four sources of light each one providing a light of a single colour- red, blue, green and yellow. Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incidence at the interface of two media is 90$°$. Which of the following statements is correct if the source of yellow light is replaced with that of other lights without changing the angle of incidence?

The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1.5, it will:

The phenomena involved in the reflection of radiowaves by ionosphere is similar to

The direction of ray of light incident on a concave mirror is shown by PQ while directions in which the ray would travel after reflection is shown by four rays marked 1, 2, 3 and 4 (figure). Which of the four rays correctly shown the direction of reflected ray?

The optical density of turpentine is higher than that of water while its mass density is lower. Figure shows a layer of turpentine floating over water in a container. For which one of the four rays incident on turpentine in figure, the path shown is correct?

A car is moving at a constant speed of 60 km h^-1 on a straight road. Looking at the rearview mirror, the driver finds that the car following him is at a distance of 100 m and is approaching with a speed of 5 km h^-1.
In order to keep track of the car in the rear, the driver begins to glance alternatively at the rear and side mirror of his car after every 2 sec till the other car overtakes, If the two cars were maintaining their speeds, which of the following statement(s) is/are correct?

There are certain materials developed in laboratories that have a negative refractive index (figure). A ray incident from the air (Medium 1) into such a medium (Medium 2) shall follow a path given by:

1.                                          2.

3.                                              4.

Consider an extended object immersed in water contained in a plane trough. When seen from close to the edge of the trough, the object looks distorted because:

(a) the apparent depth of the points close to the edge are nearer the surface of the water compared to the points away from the edge
(b) the angle subtended by the image of the object at the eye is smaller than the actual angle subtended by the object in the air
(c) some of the points of the object far away from the edge may not be visible because of total internal reflection
(d) water in a trough acts as a lens and magnifies the object