71
What is the unit of work?
A.
B.
C.
D.
Answer & Solution
Answer:
Horse powerJoule
is the amount of work done when a force of one newton displaces a mass through a distance of one meter in the direction
of that force. It is the unit of energy in the International System of Units (SI). It is named after
the English physicist James Prescott Joule.
72
If a pendulum clock is moved from the equator to the pole, the clock __________ .
A.
B.
C.
D.
Answer & Solution
Answer:
will be fastA pendulum clock will be faster at the pole than it does at the equator due to the rotation of the
earth.
73
The period of oscillation of a pendulum depends on ________ .
A.
B.
C.
D.
Answer & Solution
Answer:
The length of the pendulum & Gravitational accelerationThe period of oscillation of
a pendulum depends on two things: the length of the pendulum and gravitational acceleration. But, neither mass nor gravitational
acceleration changes oscillating period
alone.
74
When does the pendulum clock go faster?
A.
B.
C.
D.
Answer & Solution
Answer:
In winterIn winter the pendulums clock goes faster and
in summer it goes slow. As in winter temperature
of the atmosphere decreases, the length of the pendulum string decreases. Hence
time period of oscillation also decreases. As a result, the pendulum
oscillations more frequently in a specified time period. Thus the pendulum clock
runs fast in winter.
75
If the length of the string of simple pendulum is increased, the period of oscillation will _________ .
A.
B.
C.
D.
Answer & Solution
Answer:
ZeroThe length of the string
affects the pendulum's oscillating period such that the longer
the length of the string, the longer the oscillating period. This also affects the frequency of the
pendulum.
76
If it is possible to move an object to the center of the earth, what kind of change in its weight will be observed there?
A.
B.
C.
D.
Answer & Solution
Answer:
Weight will be zeroWeight is nothing but force
of gravity on an object. Since force on an object at the center is zero, weight
will be zero too.
77
Where is the lowest weight of any object?On the surface of the earth
A.
B.
C.
D.
Answer & Solution
Answer:
At equatorial regionThe centrifugal force caused by Earth's rotation is
strongest at the equator, reducing the effect of gravity there. This makes an
object's weight slightly less at the equator compared to other locations.
78
The weight of an object when it is moved from the equator to the pole _________ .
A.
B.
C.
D.
Answer & Solution
Answer:
IncreasesThe weight of an object increases as it is
moved from the equator to the north pole of the earth because at the pole the
gravitational acceleration is highest.
79
Where is the value of gravitational acceleration the highest?
A.
B.
C.
D.
Answer & Solution
Answer:
At the poleThe value of gravitational
acceleration (g) is highest at the poles and minimum
at the equator. It can be
realized from the formula g = GM/R² which is used to calculate gravitational
acceleration. Therefore, gravitational acceleration is inversely proportional
to the radius of Earth.
80
Why do the planets of the star revolve around it?
A.
B.
C.
D.
Answer & Solution
Answer:
For the attraction of planets and stars.Planets revolve around stars because of the gravitational attraction
between the two. The star's gravity pulls the planets towards it, while the
planets' motion keeps them in orbit around the star. This mutual gravitational
force is what governs the orbital movement of planets.
