71.
Which of the following is optical illusion?

72.
One can distinguish a telescope from a microscope by observing

73.
Electron microscope works on which of the following principles?

74.
Holography is a technique of

75.
Optical fiber works on the principle of

76.
Which one of the following is the correct sequence of passage of light in a compound microscope?

77.
In a Cinema hall, the distance between the projector and the screen is increased by 2%. Then the intensity of illumination on the screen is

78.
A simple microscope consists of :

79.
Person who is colourblind cannot distinguish between

80.
Fiber optics cable used in communication, works on the principle of