71. Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.Short waves are more energetic than long waves.
B.Short waves are unaffected by atmospheric disturbances.
C.Short wave broadcasts are made by nearby radio stations.
D.By convention, short waves are meant for long distances, whereas long waves are reserved for short distances.
72. When the barometer reading dips suddenly, it is an indication of?
73. Good conductor of electricity is?
74. Which of the following is a nonrenewable source of energy?
75. Solar energy is converted into chemical energy during?
76. The term 'equinox' means?
A.The path which the Earth takes around the Sun
B.The axis of the Earth around which it rotates
C.When the day and night are of equal duration
D.The time when the Sun seems to be going round and round in the sky in the Arctic but does not go below the horizon
77. Heat from the Sun reaches the Earth by?
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