26.Though the temperature inside lighted electric bulb is around 2700 degree C, the filament does not burn because :

27.Soldiers crossing a suspension bridge, always break steps, in case the frequency of vibration of their marching should coincide with that of the bridge and this is because of the phenomenin of :

28.If a pendulum clock be taken from the earth to a revolving artificial satellite, it will :

29.If the distance between the earth and the sun were twice what it is now, the gravitational force exerted on the earth by the sun would be :

30.The atmosphere exerts enormous pressure on us. But we do not feel it because :