Ray Optics and Optical Instruments

When an object is placed 40 cm away from a spherical mirror an image of magnification 12 is produced. To obtain an image with magnification of 13, the object is to be moved :

1. 20 cm away from the mirror.
2. 20 cm towards the mirror.
3. 80 cm away from the mirror.
4. 40 cm away from the mirror.

Distance between object and its image (magnified by - 13) is 30 cm. The focal length of the mirror used is ( x4 )cm, where magnitude of value of x is .

A finite size object is placed normal to the principal axis at a distance of 30 cm from a convex mirror of focal length 30 cm. A plane mirror is now placed in such a way that the image produced by both the mirrors coincide with each other. The distance between the two mirrors is :

1. 45 cm
2. 15 cm
3. 22.5 cm
4. 7.5 cm

Consider following statements for refraction of light through prism, when angle of deviation is minimum. Choose the correct answer from the options given below :

1. A, B and E Only
2. B, C and D Only
3. B, D and E Only
4. A, C and D Only

The radii of curvature for a thin convex lens are 10 cm and 15 cm respectively. The focal length of the lens is 12 cm. The refractive index of the lens material is

1. 1.4
2. 1.8
3. 1.5
4. 1.2

A monochromatic light of frequency 5 1014 Hz travelling through air, is incident on a medium of refractive index '2'. Wavelength of the refracted light will be:

1. 400 nm
2. 300 nm
3. 600 nm
4. 500 nm

Light from a point source in air falls on a spherical glass surface (refractive index, = 1.5 and radius of curvature = 50 cm). The image is formed at a distance of 200 cm from the glass surface inside the glass. The magnitude of distance of the light source from the glass surface is m.

[figure] A spherical surface separates two media of refractive indices 1 and 1.5 as shown in figure. Distance of the image of an object 'O', is : (C is the center of curvature of the spherical surface and R is the radius of curvature)

1. 0.24 m left to the spherical surface
2. 0.24 m right to the spherical surface
3. 0.4 m left to the spherical surface
4. 0.4 m right to the spherical surface

A slanted object AB is placed on one side of convex lens as shown in the diagram. The image is formed on the opposite side. Angle made by the image with principal axis is : [figure]

1. -
2. - 2
3. -45
4. +45

Two identical objects are placed in front of convex mirror and concave mirror having same radii of curvature of 12 cm, at same distance of 18 cm from the respective mirrors. The ratio of sizes of the images formed by convex mirror and by concave mirror is :

1. 2
2. 1/2
3. 1/3
4. 3