22. A circular plate, a cube and a sphere is made up of same material having the same mass, all heated to 300?C and left in a room, Which of them will have the slowest rate of cooling?
D.A11411 cools at the same rate
23. Optic fibers are used in :
24. Tw waves, each of amplitude 1.5nm and frequency 10 Hz are travelling in opposite direction with a speed of 20 m/s.The distance in mm between adjacent nodes is ?
25. The snow on the mountains does NOT melt all at once when it is heated by the sun because ?
A.it becomes very hard
B.It reflects most of the heat from the sun
C.It has a law specific heat
D.It has a nigh la tent heat of fusion
26. A person standing on a railway platform listens to the whistles of arriving and departing trains, The whistle heard is?
A.the same in both cases in all respects
B.of higher intensity when train arrives
C.of higher pitch when train arrives
D.of higher pitch when train departs
27. Holography is a technique of?
A.recording a permanent, sharp two dimensional black and white or multicolor photograph
B.Recording a permanent three dimensional multicolor photograph
C.Recording a permanent three dimensional black and white photograph
D.Recording a permanent three dimensional photograph of a given single color or a multicolor
28. Boyle's Law holds good for any gas at?
A.High temperature and low pressures
B.High temperature and high pressures
C.Low temperature and high pressures
D.Low temperature and low pressures
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