Ray Optics and Optical Instruments

A symmetric thin biconvex lens is cut into four equal parts by two planes AB and CD as shown in figure. If the power of original lens is 4D then the power of a part of the divided lens is [figure]

1. 2D
2. 8D
3. 4D
4. D

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

1. Statement I is false but Statement II is true
2. Both Statement I and Statement II are false
3. Both Statement I and Statement II are true
4. Statement I is true but Statement II is false

The following figure represents two biconvex lenses L1 and L2 having focal length 10 cm and 15 cm respectively. The distance between L1 & L2 is : [figure]

1. 25 cm
2. 35 cm
3. 10 cm
4. 15 cm

Critical angle of incidence for a pair of optical media is 45 . The refractive indices of first and second media are in the ratio:

1. 1 : 2
2. 1 : 2
3. 2 : 1
4. 2 : 1

The position of the image formed by the combination of lenses is : [figure]

1. 15 cm (right of second lens)
2. 30 cm (right of third lens)
3. 30 cm (left of third lens)
4. 15 cm (left of second lens)

The refractive index of prism is = 3 and the ratio of the angle of minimum deviation to the angle of prism is one. The value of angle of prism is .

For the thin convex lens, the radii of curvature are at 15 cm and 30 cm respectively. The focal length of the lens is 20 cm. The refractive index of the material is :

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

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

1. Both Statement I and Statement II are true
2. Statement I is true but Statement II is false
3. Statement I is false but Statement II is true
4. Both Statement I and Statement II are false

An effective power of a combination of 5 identical convex lenses which are kept in contact along the principal axis is 25D. Focal length of each of the convex lens is:

1. 50 cm
2. 20 cm
3. 25 cm
4. 500 cm

A light ray is incident on a glass slab of thickness 4 3 cm and refractive index 2. The angle of incidence is equal to the critical angle for the glass slab with air. The lateral displacement of ray after passing through glass slab is cm. (Given 15 = 0.25)