# Questions on Simple Pendulum ### Simple pendulum Questions and Answers:

Ques: The period of a simple pendulum is doubled, when
(a) Its length is doubled
(b) The mass of the bob is doubled
(c) Its length is made four times
(d) The mass of the bob and the length of the pendulum are doubled

Ans. (c)

Ques: The period of oscillation of a simple pendulum of constant length at earth surface is T. Its period inside a mine is
(a) Greater than T
(b) Less than T
(c) Equal to T
(d) Cannot be compared

Ans. (a)

Ques: The length of a simple pendulum is increased by 44%. What is the percentage increase in its time period ?
(a) 10%
(b) 20%
(c) 40%
(d) 44%

Ans. (b)

Ques: A pendulum suspended from the ceiling of a train has a period T, when the train is at rest. When the train is accelerating with a uniform acceleration a, the period of oscillation will
(a) Increase
(b) Decrease
(c) Remain unaffected
(d) Become infinite
Asns. (b)

Ques: Which of the following statements is not true ? In the case of a simple pendulum for small amplitudes the period of oscillation is
(a) Directly proportional to square root of the length of the pendulum
(b) Inversely proportional to the square root of the acceleration due to gravity
(c) Dependent on the mass, size and material of the bob
(d) Independent of the amplitude

Ans. (c)

Ques: The length of the second pendulum on the surface of earth is 1 m. The length of seconds pendulum on the surface of moon, where g is 1/6th value of g on the surface of earth, is
(a) 1 / 6 m
(b) 6 m
(c) 1 / 36 m
(d) 36 m

Ans. (a)

Ques: The period of simple pendulum is measured as T in a stationary lift. If the lift moves upwards with an acceleration of 5 g, the period will be
(a) The same
(b) Increased by 3/5
(c) Decreased by 2/3 times
(d) None of the above

Ans. (d)

Ques: A simple pendulum executing S.H.M. is falling freely along with the support. Then
(a) Its periodic time decreases
(b) Its periodic time increases
(c) It does not oscillate at all
(d) None of these

Ans. (c)

Ques: If the metal bob of a simple pendulum is replaced by a wooden bob, then its time period will
(a) Increase
(b) Decrease
(c) Remain the same
(d) First increase then decrease

Ans. (c)

Ques: In a seconds pendulum, mass of bob is 30 gm. If it is replaced by 90 gm mass. Then its time period will
(a) 1 sec
(b) 2 sec
(c) 4 sec
(d) 3 sec

Ans. (b)

Ques: The length of a seconds pendulum is
(a) 99.8 cm
(b) 99 cm
(c) 100 cm
(d) None of these

Ans. (b)

Ques: A simple pendulum, suspended from the ceiling of a stationary van, has time period T. If the van starts moving with a uniform velocity the period of the pendulum will be
(a) Less than T
(b) Equal to 2T
(c) Greater than T
(d) Unchanged

Ans. (d)

Ques: To show that a simple pendulum executes simple harmonic motion, it is necessary to assume that
(a) Length of the pendulum is small
(b) Mass of the pendulum is small
(c) Amplitude of oscillation is small
(d) Acceleration due to gravity is small

Ans. (c)

Ques: A chimpanzee swinging on a swing in a sitting position, stands up suddenly, the time period will
(a) Become infinite
(b) Remain same
(c) Increase
(d) Decrease

Ans. (d)

Ques: A plate oscillated with time period ‘T’. Suddenly, another plate put on the first plate, then time period
(a) Will decrease
(b) Will increase
(c) Will be same
(d) None of these

Ans. (c)

Ques: A simple pendulum hangs from the ceiling of a car. If the car accelerates with a uniform acceleration, the frequency of the simple pendulum will
(a) Increase
(b) Decrease
(c) Become infinite
(d) Remain constant

Ans. (a)

Ques: Two pendulums begin to swing simultaneously. If the ratio of the frequency of oscillations of the two is 7 : 8, then the ratio of lengths of the two pendulums will be
(a) 7 : 8
(b) 8 : 7
(c) 49 : 64
(d) 64 : 49

Ans. (d)

Ques: If the length of a pendulum is made 9 times and mass of the bob is made 4 times then the value of time period becomes
(a) 3T
(b) 3/2T
(c) 4T
(d) 2T

Ans. (a)

Ques: A simple pendulum has a time period T1 when on the earth’s surface and T2 when taken to a height R above the earth’s surface, where R is the radius of the earth. The value of T2/T1 is
(a) 1
(b) ½
(c) 4
(d) 2

Ans. (d)

Ques: Time period of a simple pendulum will be double, if we
(a) Decrease the length 2 times
(b) Decrease the length 4 times
(c) Increase the length 2 times
(d) Increase the length 4 times

Ans. (c)

Related: question of Unit and Dimension

Ques: The velocity of simple pendulum is maximum at
(a) Extremes
(b) Half displacement
(c) Mean position
(d) Every where

Ans. (c)

Ques: What effect occurs on the frequency of a pendulum if it is taken from the earth surface to deep into a mine
(a) Increases
(b) Decreases
(c) First increases then decrease
(d) None of these

Ans. (b)