Gen. Science

57)Which one of the following statements is correct?
All bases are alkalis. None of the bases is alkali.
There are no more bases except the alkalis. All alkalis are bases but all bases are not alkalis.
Answer :

58)A liquid is kept in a regular cylindrical vessel up to a certain height. If this vessel is replaced by another cylindrical vessel, having half the area of cross-section of the bottom, the pressure on the bottom will
remain same. be reduced to half the earlier pressure.
be double the earlier pressure. be reduced to one fourth the earlier pressure.
Answer :

59)The time period of a simple pendulum having a spherical wooden bob is 2sec. If the bob is replaced by a metalic one twice as heavy, the time period will be
more than 2sec. 2sec.
less than 2sec. 1sec.
Answer :

60)Which one of the following statements about an atom is not correct?
Atoms always combine to form molecules. Atoms are the basic units from which molecules and ions are formed.
Atoms are always neutral in nature. Atoms aggregate in large numbers to form the matter that we can see, feel and touch.
Answer :

61)The swing of a spinning cricket ball in the air can be explained on the basis of
sudden change in wind direction buoyancy of air
turbulence caused by wind Bernoulli\'s theorem
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62)A train past a railway station at a high speed. A boy standing on the edge of the platform is likely to
remain unaffected fall away from the train
fall towards the train none of these
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63)In a sprayer the liquid rises in the tube due to
capillarity evaporation
lower pressure at the upper end none of these
Answer :

64)A football bounces when it falls on the ground because
it is made up of rubber it hollow
it is very light and is able to overcome the resistance of air of the of elasticity
Answer :

65)Tee study of science dealing with the phenomena at at very low temperatures is known as
refrigenics cytrogenics
frozenics cryogenics
Answer :

66)In cold countries alcohol is preferred to mercury as a thermometric liquid because
alcohol is better conductor of heat alcohol can be coloured and its level seen easily
alcohol has a very low freezing point alcohol is cheaper than mercury
Answer :

67)On heating a circular metallic disc with a circular hole at the centre, the diameter of the hole will
dicrease remain the same
increase first increase then decrease
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68)A certain mass of liquid is heated in a glass flask
the density of the liquid remain unchanged the liquid level starts rising at once
the liquid level falls at first and then starts rising the density of the liquid increases
Answer :

69)When a cube of floating ice melts in a beaker the water level in the beaker will
rise fall
remain same none of these
Answer :

70)The temperature of the top of a frozen lake is -15 degree Celsius. What is the temperature of the water in the lake in contact with the ice layer?
0 degree Celsius 4 degree Celsius
-15 degree Celsius -7.5 degree Celsius
Answer :

71)Fish can survive in a frozen lake because
fish is warm blooded animal fish hibernates in ice
water near the bottom of the lake does not freeze ice is a good conductor of heat
Answer :

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