Geometrical optics

The speed of light in vacuum is about:

• 1 3 x 10⁶ m/s
• 2 3 x 10¹⁰ m/s
• 3 340 m/s
• 4 3 x 10⁸ m/s

A concave mirror is also called a:

• 1 Prism
• 2 Plane mirror
• 3 Converging mirror
• 4 Diverging mirror

The focal length of a mirror of radius of curvature 20 cm is:

• 1 40 cm
• 2 10 cm
• 3 20 cm
• 4 5 cm

Total internal reflection occurs when light goes from:

• 1 Rare to dense medium
• 2 Dense to rare medium above the critical angle
• 3 Air to vacuum
• 4 Any medium at 0 degrees

A convex lens is used to correct:

• 1 Long sight
• 2 Astigmatism only
• 3 Short sight
• 4 Colour blindness

The power of a lens of focal length 0.5 m is:

• 1 0.5 D
• 2 2 D
• 3 1 D
• 4 5 D

The image formed by a plane mirror is:

• 1 Real and inverted
• 2 Virtual and inverted
• 3 Real and upright
• 4 Virtual and upright

A convex lens is also called a:

• 1 Prism
• 2 Plane lens
• 3 Converging lens
• 4 Diverging lens

The bending of light as it passes from one medium to another is:

• 1 Dispersion
• 2 Diffraction
• 3 Reflection
• 4 Refraction

White light splits into colours in a prism. This is called:

• 1 Diffraction
• 2 Polarisation
• 3 Dispersion
• 4 Reflection