Simple Pendulum & Compound Pendulum — Practice Questions

Free NEET Physics multiple-choice questions on Simple Pendulum & Compound Pendulum. Attempt each question and reveal the answer with a full explanation.

The period of a simple pendulum is T . If the length is increased by 21 % , the time period increases by: 10 % 21 % 44 % 11 % A simple pendulum is placed in a satellite orbiting the Earth. Its time period will be: Infinite Zero 2 seconds Same as on Earth surface A simple pendulum is suspended from the ceiling of a lift which is falling freely. The frequency of oscillation will be: Zero Infinite Same as on Earth Cannot be determined The length of a simple pendulum is increased by 44 % . What is the percentage increase in its time period? 20 % 44 % 22 % 10 % A point source emits sound equally in all directions in a non-absorbind medium. Two points P and Q are at distance of 2 m and 3 m respectively from the source. The ratio of the intensities of the waves at P and Q is - 3:2 2:3 9:4 4:9 Two sound waves with wavelength 5.0 m and 5.5 respectively, each propagate in a gas with velocity 330 m/s. We expect the following number of beats per second:- 12 0 1 6 A transverse wave propagating along x-axis is represented by y(x,t) = 8.0 (0.5 x - 4 t - 4 ) where x is in metres and t is in seconds. The speed of the wave is:- 4 m/s 0.5 m/s 4 m/s 8 m/s Which one of the following statements is true: Both light and sound waves in air are transverse The sound waves in air are longitudinal while the light waves are transverse Both light and sound waves in air are longitudinal Both light and sound waves can travel in vacuum A wave travelling in the +ve x -direction having displacement along y -direction as 1 m, wavelength 2 m and frequency of 1 Hz is represented by y = (x - 2t) y = (2 x - 2 t) y = (10 x - 20 t) y = (2 x + 2 t) Due to Doppler effect, the shift in wavelength observed is 0.1 , for a star producing a wavelength 6000 . The velocity of recession of the star will be : 20 km s -1 2.5 km s -1 10 km s -1 5 km s -1 If the initial tension on a stretched string is doubled, then the ratio of the initial and final speeds of a transverse wave along the string is 2 : 1 1 : 2 1 : 2 1 : 1 If the length of a simple pendulum is increased by 2 % , the time period of the pendulum will: Increase by 1% Increase by 2% Decrease by 1% Increase by 4% For a travelling harmonic wave y(x, t)=2.0 2 (10t-0.0080x+0.35) , where x and y are in cm and t in s. The phase difference between oscillatory motion of two points separated by a distance of 0.5 m is: 0.08 rad 0.008 rad 0.8 rad 8 rad A simple pendulum is suspended from the roof of a trolley which moves in a horizontal direction with an acceleration a , then the time period is given by T = 2 l/g' , where g' is: g 2 + a 2 g + a g - a g 2 - a 2 The time period of a simple pendulum of infinite length is: (where R is the radius of Earth) 2 R/g Infinite 2 g/R Zero A simple pendulum is hanging from the ceiling of a lift. If the lift moves up with an acceleration a , the time period of the pendulum will be: T = 2 l g+a T = 2 l g-a T = 2 l g T = 2 l g 2+a 2 A simple pendulum of period T has a metal bob which is negatively charged. If it is allowed to oscillate above a positively charged metal plate, its new time period will be: Less than T Greater than T Equal to T Infinite A simple pendulum is suspended from the roof of a car. If the car rounds a curve of radius R with a constant speed v , the time period of the pendulum is T = 2 l/g' , where g' is: g 2 + (v 2/R) 2 g + v 2/R g - v 2/R g 2 + v 2/R If the length of a simple pendulum is decreased by 2 % , the time period will: Decrease by 1 % Decrease by 2 % Increase by 1 % Increase by 2 % A uniform rod of length L is pivoted at one of its ends and oscillates as a physical pendulum. The time period of its small oscillations is: 2 2L/3g 2 L/g 2 L/2g 2 3L/2g A simple pendulum of length L has a maximum angular displacement . The maximum velocity of the bob is: 2gL(1 - ) gL(1 - ) 2gL 2gL If the period of a simple pendulum is T on the surface of Earth, its period at a height R (radius of Earth) above the surface is: 2T 4T T/2 2 T A simple pendulum is taken from the equator to the pole. Its time period will: Decrease Increase Remain the same First increase then decrease A simple pendulum is suspended from the ceiling of a car moving horizontally with an acceleration a = g . The time period of small oscillations of the pendulum is given by T = 2 l g' , where g' is equal to: 2 g g 2g g/ 2 A simple pendulum has a time period T on Earth. If it is taken to another planet where both the mass and radius are double those of the Earth, the new time period will be: 2 T T/ 2 T 2T A simple pendulum of length L has a time period T . If the pendulum is placed in a lift moving upwards with an acceleration a = g/3 , the new time period T' will be: 3 2 T 2 3 T 3 T T/ 3 A simple pendulum is suspended from the roof of a truck which is moving with a horizontal acceleration a . The time period of small oscillations is T = 2 l/g' , where g' is: g 2 + a 2 g + a g - a g 2 - a 2 The time of reverberation of a room A is one second. What will be the time (in seconds) of reverberation of a room, having all the dimensions double of those of room A- 2 4 1 2 1 The driver of a car traveling with speed 30 m/sec towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is : 500 Hz 550 Hz 555.5 Hz 720 Hz A wave in a string has an amplitude of 2 cm. The wave travels in the +ve direction of x-axis with a speed of 128 m/s and it is noted that 5 complete waves fit in 4 m length of the string. The equation describing the wave is y=(0.02) m (7.58x-1005 t) y=(0.02) m (7.85x+1005 t) y=(0.02) m (15.7x-2010 t) y=(0.02) m (15.7x+2010 t) A speeding motorcyclist sees traffic jam ahead of him. He slows down to 36 km/hour. He finds that traffic has eased and a car moving ahead of him at 18 km/hour is honking at a frequency of 1392 Hz. If the speeds of sound is 343 m/s, the frequency of the honk as heard by him will be :- 1332 Hz 1372 Hz 1412 Hz 1464 Hz A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of 15 , ms -1 . Then, the frequency of sound that the observer hears in the echo reflected from the cliff is : (Take velocity of sound in air = 330 , ms -1 ) 765 Hz 800 Hz 838 Hz 885 Hz A uniform rope of length L and mass m 1 hangs vertically from a rigid support. A block of mass m 2 is attached to the free end of the rope. A transverse pulse of wavelength 1 is produced at the lower end of the rope. The wavelength of the pulse when it reaches the top of the rope is 2 . The ratio 2/ 1 is : m 1 m 2 m 1+m 2 m 2 m 2 m 1 m 1+m 2 m 1 The length of a simple pendulum is l . If the mass of the bob is doubled, the time period will: Remain the same Be doubled Be halved Become 2 times A pipe open at both ends has a fundamental frequency f in air. The pipe is now dipped vertically in a water drum to half of its length. The fundamental frequency of the air column is now equal to: 2f f 2 f 3f 2 A hollow sphere is filled with water and used as the bob of a simple pendulum. If water slowly leaks out of a small hole at the bottom, the time period will: First increase then decrease Remain constant Continuously increase Continuously decrease A simple pendulum with a bob of mass m and charge +q is suspended in a uniform vertical electric field E directed downwards. The time period of the pendulum is: 2 l g + qE/m 2 l g - qE/m 2 l g 2 l g 2 + (qE/m) 2 A simple pendulum has a time period T in vacuum. If the bob of the pendulum is immersed in a non-viscous liquid of density , and the density of the material of the bob is , what is the new time period T' ? T - T - T - T A liquid of density is filled in a U-tube to a height h . If the liquid column is slightly depressed in one limb and released, the time period of oscillation is: 2 h/g 2 2h/g 2 h/2g h/g A vertical cylinder of cross-sectional area A and mass M floats in a liquid of density . If it is slightly depressed and released, its time period of oscillation is: 2 M A g 2 A g M 2 M Lg 2 M Ag The length of a second's pendulum on the surface of Earth ( g = 9.8 m/s 2 ) is approximately: 1.0 m 0.5 m 2.0 m 9.8 m The acceleration due to gravity on the Moon is 1/6 of that on Earth. If a simple pendulum has a period T on Earth, its period on the Moon will be: 6 T 6T T/6 T/ 6 If the length of a simple pendulum is halved and its mass is doubled, its period becomes: T/ 2 2 T T 2T A torsional pendulum consists of a wire with a torsional constant C and a disc of moment of inertia I . The time period of its angular oscillations is given by: T = 2 I/C T = 2 C/I T = 2 IC T = 1 2 I/C A spring-mass system is placed on a frictionless incline of angle . The time period of oscillation is: 2 m/k 2 m / k 2 m / (k ) 2 m / k