Physics M.C.Q (1 Marks)

A spectrum is formed by a prism of dispersive power ‘ω’. If the angle of deviation is ‘δ’, then the angular dispersion is

Fraunhofer lines are obtained in

A prism (μ = 1.5) has the refracting angle of 30°. The deviation of a monochromatic ray incident normally on its one surface will be (sin 48° 36’ = 0.75)

We use flint glass prism to disperse polychromatic light because light of different colours

The critical angle between an equilateral prism and air is 45°. If the incident ray is perpendicular to the refracting surface, then

Formula for dispersive power is (where symbols have their usual meanings)

Which source is associated with a line emission spectrum

The dispersive power of the material of lens of focal length 20 cm is 0.08. The longitudinal chromatic aberration of the lens is

The focal length of the field lens (which is an achromatic combination of two lenses) of telescope is 90 cm. The dispersive powers of the two lenses in the combination are 0.024 and 0.036. The focal lengths of two lenses are

A concave lens and a convex lens have same focal length of 20 cm and both put in contact this combination is used to view an object 5 cm long kept at 20 cm from the lens combination. As compared to object the image will be

If two lenses of +5 diopters are mounted at some distance apart, the equivalent power will always be negative if the distance is

The plane faces of two identical plano-convex lenses each having focal length of 40 cm are pressed against each other to form a usual convex lens. The distance from this lens, at which an object must be placed to obtain a real, inverted image with magnification one is

A thin glass (refractive index 1.5) lens has optical power of -5D in air. It's optical power in a liquid medium with refractive index 1.6 will be

A convex lens is in contact with concave lens. The magnitude of the ratio of their focal length is 2/3. Their equivalent focal length is 30 cm. What are their individual focal lengths

When light rays from the sun fall on a convex lens along a direction parallel to its axis

Two lenses of power + 12 and – 2 diopters are placed in contact. The combined focal length of the combination will be

An equiconvex lens is cut into two halves along (i) XOX¢ and (ii) YOY¢ as shown in the figure. Let f, f ¢, f ¢¢ be the focal lengths of the complete lens, of each half in case (i), and of each half in case (ii), respectively

Choose the correct statement from the following

A bi-convex lens made of glass (refractive index 1.5) is put in a liquid of refractive index 1.7. Its focal length will

A combination of two thin convex lenses of focal length 0.3 m and 0.1 m will have minimum spherical and chromatic aberrations if the distance between them is

The radius of the convex surface of plano-convex lens is 20 cm and the refractive index of the material of the lens is 1.5. The focal length of the lens is
 

A plano-convex lens is made of refractive index of 1.6. The radius of curvature of the curved surface is 60 cm. The focal length of the lens is

At what distance from a convex lens of focal length 30 cm, an object should be placed so that the size of the image be 1/2 of the object

A plano-convex lens of refractive index 1.5 and radius of curvature 30 cm is silvered at the curved surface. Now this lens has been used to form the image of an object. At what distance from this lens an object be placed in order to have a real image of the size of the object

In order to obtain a real image of magnification 2 using a converging lens of focal length 20 cm, where should an object be placed

A point object is placed at the center of a glass sphere of radius 6 cm and refractive index 1.5. The distance of the virtual image from the surface of the sphere is

A thin plano-convex lens acts like a concave mirror of focal length 0.2 m when silvered from its plane surface. The refractive index of the material of the lens is 1.5. The radius of curvature of the convex surface of the lens will be

A beam of parallel rays is brought to a focus by a plano-convex lens. A thin concave lens of the same focal length is joined to the first lens. The effect of this is

An object placed 10 cm in front of a lens has an image 20 cm behind the lens. What is the power of the lens (in dioptres)

A magnifying glass is to be used at the fixed object distance of 1 inch. If it is to produce an erect image magnified 5 times its focal length should be

In a parallel beam of white light is incident on a converging lens, the colour which is brought to focus nearest to the lens is

An achromatic combination of lenses produces

When the convergent nature of a convex lens will be less as compared with air

If aperture of lens is halved then image will be

The chromatic Aberration in lenses becomes due to

A lens of power + 2 diopters is placed in contact with a lens of power – 1 diopoter. The combination will behave like

A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will

A double convex thin lens made of glass of refractive index 1.6 has radii of curvature 15 cm each. The focal length of this lens when immersed in a liquid of refractive index 1.63 is

A point object O is placed in front of a glass rod having spherical end of radius of curvature 30 cm. The image would be formed at

If convex lens of focal length 80cm and a concave lens of focal length 50 cm are combined together, what will be their resulting power

An object is placed 12 cm to the left of a converging lens of focal length 8 cm. Another converging lens of 6 cm focal length is placed at a distance of 30 cm to the right of the first lens. The second lens will produce

A convex lens is made up of three different materials as shown in the figure. For a point object placed on its axis, the number of images formed are