Optics

The refractive indices of the material of the prism for red and yelow colour are 1.620 and 1.635 respectively. Calculate the refractive index for violet colour

• 3.27

• 1.620

• 1.65

• 1.72

this is an example of

• refraction

• diffraction

• infraction

• reflection

The point in the middle way between a curved mirror and the center of curvature is the

• principle point
• focal point
• center of curvature
• principle axis

The line that passes through the center of a curved mirror is called

• focal point
• center of curvature 
• principle axis
• light ray

The focal length is equal to the:

• radius of curvature
• diameter of curvature
• half radius of curvature
• half diameter of curvature

A point object is kept 10 cm away from a double convex lens of refractive index 1.5 and radii of curvature 10 cm and 8 cm . Find focal length of the lens.

• 9/40

• 40/9

• 80/9

• 9/80

For a dense flint glass prism of refracting angle 10 ⁰ , obtain angular deviation for violet. Given n _violet = 1.792.

• 17.9

• 10.9

• 7.92

• 0.792

For a person seeing an object placed in optically rarer medium

• Apparent depth of the object is more than real depth

• Apparent depth is smaller than the real depth

• apparent depth might be smaller or greater depending on the position of the person

• nothing can be concluded about the depth of object from given data

Angles of deviation for extreme colours are given for different prisms. Select the one having maximum dispersive power of its material.

• 7 ⁰ , 10 ⁰

• 8 ⁰ , 11 ⁰

• 12 ⁰ , 16 ⁰

• 10 ⁰, 14 ⁰