OPTICAL INSTRUMENTS

The angular magnification of a system is less than one. Does it mean that the image formed is inverted?

• Yes

• No

To increase the angular magnification of a simple microscope, one should increase:

• the focal length of the lens

• the power of the lens

• the aperture of the lens

• the object size

An optical instrument used for magnification has power 25 D of objective and 20 D of eyepiece. Whether it is a microscope or a telescope?

• Microscope

• Telescope

The eyepiece of an astronomical telescope has a focal length of 10 cm. The telescope is focused for normal vision of distant objects when the tube length is 1 m. The focal length of the objective is:

• 20 cm

• 10 cm

• 90 cm

• 100 cm

The magnifying power of an astronomical telescope is 8 and the distance between the two lenses is 54 cm. The focal length of eye lens and objective lens will be respectively:

• 6 cm and 48 cm

• 48 cm and 6 cm

• 8 cm and 64 cm

• 64 cm and 8 cm

Finger prints are observed by the use of :

• Telescope

• Microscope

• Newtonian telescope

• Concave lens

If the focal length of the objective lens is increased then,

• Magnifying power of microscope will increase but that of telescope will decrease

• Magnifying power of microscope and telescope both will increase

• Magnifying power of microscope and telescope both will decrease

• Magnifying power of microscope will decrease but that of telescope will increase

The magnification produced by the objective lens and the eye lens of a compound microscope are 25 and 6 respectively. The magnifying power of this microscope is:

• 19

• 31

• 150

• 120

The objective of a compound microscope is essentially:

• A concave lens of small focal length and small aperture

• Convex lens of small focal length and large aperture

• Convex lens of large focal length and large aperture

• Convex lens of small focal length and small aperture

A compound microscope has two lenses. The magnifying power of one is 5 and the combined magnifying power is 100. The magnifying power of the other lens is:

• 10

• 20

• 50

• 25