Light colours absorb less heat therefore these are not heated as
much as the black colour.
Ans: Dark colours do
not exactly absorb more heat, but they do convert a higher percentage of light
into heat. In the sun with a dark coloured shirt it gets hot, where a lighter
coloured shirt would not get nearly as hot. This is due to the amount of light
being absorbed by the colour. The lighter the colour the smaller is the range
of visible light being absorbed and converted into heat. White objects reflect
all visible light, where black objects absorb all visible light.
Rain water is more fertile than water from tube well.
Ans: Rain water is more
fertile because it contains many salts and nitrogen dissolved from the
atmosphere.
The manhole covers are generally round.
Ans: Manholes, which
interconnect underground sewerage pipes, and serve as a point of entry for
cleaning the pipes, are located at every major sewer pipe junction, and are
capped with round manhole covers. The reason for the circular construction of
these covers is, quite simply, that covers of any other shape would fall
through the manholes by virtue of their varying diameters. Circular manhole
covers do not vary in width, or in diameter, as is the case with these other shapes,
thus remaining in place despite the street traffic running roughshod over them.
Clothes of a moving dancer bulge.
Ans: The clothes of a
moving dancer bulge outside due to the centrifugal force which tends to move
away from the centre.
People are advised not to stand near fast moving train.
Ans: One should not
stand beside a fast moving train because of the strong pressure of air which
carries along. A man can fall in this pressure.
The image of a tree is inverted on the bank of a lake.
Ans: The water of lake
acts as a mirror. According to the laws of light, mirror forms inverted images.
Polar star is always seen in the north.
Ans: It is because the
Polar Star (North Star) is closest to the location of the celestial North Pole.
We never see birds urinating.
Ans: The birds do not
have a urinary system like other living beings which possess urinary excretory
organs. In the birds the urine is excreted from body without special organs.
Pasteurized milk has more nourishment than the ordinary boiled milk.
Ans: Pasteurized milk
is obtained by heating milk at a temperature of 60 degree Celsius for 30
minutes. In this way the TB bacteria are killed without damaging the milk
protein. Thus pasteurized milk has more nourishment than ordinary boiled milk.
Bees die when they sting human being.
Ans: Their stingers are
actually ovipositors, tubular structures extending from the abdomen that
sometimes contain eggs. When the barbed stinger is left inside the victim, the
honeybee mortally tears her abdomen in the process. They leave their stingers
in the wound with a tiny venom sac attached. Fortunately, only about one out of
a hundred people are allergic to bee sting, but allergic reactions can be very
serious.
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