71.
Which one type of radiation has the longest wave length

72.
Forged documents are detected by

73.
The radiation initially produced in fluorescent tube is

74.
In a vacuum, all electromagnetic waves have the same

75.
Ultra violet radiations of the Sun do not reach the earth because, earth's atmosphere is surrounded by

76.
Which one among the following is not an electromagnetic wave?

77.
Electromagnetic waves are transverse in nature is evident by

78.
Which of the following parts of the sunlight makes the solar cooker hot ?

79.
In the atmosphere ultraviolet rays are absorbed by

80.
Energy of Ultraviolet rays is great than