Ray Optics and Optical Instruments

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below:

1. Both (A) and (R) are correct and (R) is the correct explanation of (A)
2. (A) is correct but (R) is not correct
3. (A) is not correct but (R) is correct
4. Both (A) and (R) are correct but (R) is not the correct explanation of (A)

A mirror is used to produce an image with magnification of 14. If the distance between object and its image is 40 cm, then the focal length of the mirror is .

1. 10 cm
2. 12.7 cm
3. 10.7 cm
4. 15 cm

A transparent block A having refractive index = 1.25 is surrounded by another medium of refractive index = 1.0 as shown in the figure. A light ray is incident on the flat face of the block with incident angle as shown in the figure. What is the maximum value of for which light suffers total internal reflection at the top surface of the block? [figure]

1. -1(4/3)
2. -1(3/4)
3. -1(3/4)
4. -1(3/4)

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.