Ray Optics and Optical Instruments · Question 46

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

A bi-convex lens has radius of curvature of both the surfaces same as 1/6 cm. If this lens is required to be replaced by another convex lens having different radii of curvature on both sides (R1 R2), without any change in lens power then possible combination of R1 and R2 is :

1. 13 cm and 17 cm
2. 15 cm and 17 cm
3. 13 cm and 13 cm
4. 16 cm and 19 cm

A ray of light suffers minimum deviation when incident on a prism having angle of the prism equal to 60 . The refractive index of the prism material is 2. The angle of incidence (in degrees) is

Let u and v be the distances of the object and the image from a lens of focal length f. The correct graphical representation of u and v for a convex lens when |u| > f, is

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Two light beams fall on a transparent material block at point 1 and 2 with angle 1 and 2, respectively, as shown in figure. After refraction, the beams intersect at point 3 which is exactly on the interface at other end of the block. Given : the distance between 1 and 2, d = 4 3 cm and 1 = 2 = -1 ( n22n1 ), where refractive index of the block n2 > refractive index of the outside medium n1, then the thickness of the block is cm. [figure]