Optical instruments

The magnifying power of a simple microscope for a near point of 25 cm and focal length 5 cm is (image at the near point):

• 1 5
• 2 25
• 3 30
• 4 6

A telescope's magnifying power (normal adjustment) is:

• 1 f objective x f eyepiece
• 2 f objective - f eyepiece
• 3 f eyepiece / f objective
• 4 f objective / f eyepiece

The human eye forms its image on the:

• 1 Cornea
• 2 Pupil
• 3 Retina
• 4 Iris

Short sight is corrected with a:

• 1 Concave lens
• 2 Plane mirror
• 3 Convex lens
• 4 Prism

In an optical fibre, light travels by:

• 1 Diffraction
• 2 Refraction only
• 3 Total internal reflection
• 4 Dispersion