General Physics
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257 A bird sitting on a high tension electric wire does not get electrocuted because
A
it has high resistance
B
the body is earthed
C
it does not form a closed
path for the flow of current
D
its feet are good insulators
258 In a refrigerator, the cooling system should always be
A
at the top
B
at the bottom
C
at the middle
D
can be anywhere
260 'Shock-absorbers' are usually made of steel as it :
A
is not brittle
B
has lower elasticity
C
has higher elasticity
D
has no ductile property
261 What is the principle of a ‘Life Jacket’?
A
It provides oxygen to a
drowning person
B
It increases the volume of
the person to keep him afloat
C
It decreases the volume of
the person to keep him afloat
D
The person can sit on it like
a raft
262 If there is a circular hole in a metal plate, what happens to the radius of the hole when the plate is heated?
A
Increases
B
Decreases
C
Unchanged
D
Depends upon the metal
265 In MRI machine, which one of the following is used?
A
Sound wave
B
‘X’-ray
C
Ultra-sound wave
D
Magnetic wave
266 Electricity is transmitted over long distances
A
it is fast
B
there is less wastage of energy
C
it is safer
D
it is cheaper