7th Chapter Solved Exercise MCQs Of FSc First Year Physics

7th Chapter Solved Exercise MCQs of FSc First Year Physics is a helpful resource for students preparing for exams, featuring solved multiple-choice questions. Each MCQ comes with a clear explanation, making it easier to understand the correct answers. Use this resource to enhance your studies and feel ready for your exams.

7th chapter solved MCQs with explanation

1. The waveform of S.H.M is:

(a) Standing wave

(b) Sine wave

(c) Square wave

(d) None of these

Explanation: Option (b) is correct: Simple harmonic motion (SHM) is a periodic motion characterized by a sine or cosine function.

2. Force needed to produce and extantion of one meter in a spring is called:

(a) Stress

(b) Strain

(c) Spring constant

(d) None of these

Explanation: Option (c) is correct: The spring constant is a measure of the stiffness of a spring. It relates the force applied to a spring to its extension or compression.

3. When the amplitude of oscillation is doubled then energy of mass spring system becomes:

(a)One half

(b) Six times

(c) Double

(d) Four times

Explanation: Option (c) is correct: The total energy of a mass-spring system is proportional to the square of the amplitude. Doubling the amplitude increases the energy by a factor of 2^2 = 4.

4. A simple pendulum suspended from the ceiling of a lift has time period T when the lift is at rest. When lift falls freely, the time period is:

(a) Infinite

(b) T/√8

(c) Zero

(d) T

Explanation: Option (d) is correct: When a lift falls freely, the gravitational acceleration acting on the pendulum becomes zero. This means the effective acceleration acting on the pendulum is also zero, resulting in an infinite time period.

5. In SHM, at extreme position, __________ is maximum:

(a) Velocity

(b) Acceleration

(c) Kinetic energy

(d) All of these

Explanation: Option (b) is correct: At the extreme positions of SHM, the velocity is zero, but the acceleration is at its maximum value.

6. The working of __________ is not based upon the principle of resonance:

(a)T.V.

(b) Radio

(c) Microwave oven

(d) Bulb

Explanation: Option (d) is correct:Resonance occurs when a system vibrates at its natural frequency. While T.V., radio, and microwave ovens operate based on resonance, a bulb does not.

7. Natural frequency of simple pendulum varies inversely with:

(a)Its mass

(b) Length

(c) Square root of length

(d) Square of length

Explanation: Option (c) is correct:The natural frequency of a simple pendulum is inversely proportional to the square root of its length.

8. Total distance travelled by bob of simple pendulum in one vibration is:

(a)Amplitude

(b) 2 times of amplitude

(c) 4 times of amplitude

(d) Square of amplitude

Explanation: Option (c) is correct: In one complete vibration, a pendulum bob travels a distance equal to 4 times its amplitude.

9. When K.E. of SHM is maximum, its:

(a) Acceleration is zero

(b) P.E. is zero

(c) All are zero

(d) Restoring force is zero

Explanation: Option (a) is correct: At the equilibrium position of SHM, the kinetic energy is maximum, and the acceleration, potential energy, and restoring force are all zero.

10. In damped harmonic oscillation, which one of them decreases?

(a) Amplitude of vibration

(b) Energy of vibration

(c) Both amplitude and energy

(d) Neither amplitude nor energy

Explanation: Option (b) is correct: In damped harmonic oscillations, energy is gradually lost due to friction or other dissipative forces, leading to a decrease in both amplitude and energy.

11. The distance covered by a body in one complete vibration is 20 cm. What is the amplitude of the body?

(a) 10 cm

(b) 5 cm

(c) 15 cm

(d) 7.5 cm

Explanation: Option (a) is correct:In one complete vibration, a pendulum bob travels a distance equal to 4 times its amplitude. Therefore, the amplitude is 20 cm / 4 = 10 cm.

12. What will be total energy of a mass attached to a spring with spring constant 2 N/m when displaced through 2 m will be:

(a) 2 J

(b) 4 J

(c) 1 J

(d) 8 J

Explanation: Option (a) is correct:The potential energy stored in a spring is given by PE = ½kx², where k is the spring constant and x is the displacement. Plugging in the values, we get PE = ½ * 2 * 2² = 4 J.

13.If the length of second pendulum is L, then length of pendulum having a period 1 sec will be:

(a) 2L

(b) L/2

(c) L/4

(d) 4L

Explanation: Option (c) is correct:The period of a simple pendulum is proportional to the square root of its length. If the period is halved, the length must be reduced to a quarter.

14. A spring of spring constant K is cut into two halves. Then the spring constant of each part will be:

(a) K/4

(b) K/2

(c) 2K

(d) 4K

Explanation: Option (c) is correct: When a spring is cut in half, its effective spring constant doubles. This is because the length of each half is halved, and the spring constant is inversely proportional to length.

15.The time period of the hour hand of a watch is:

(a) 1 hr

(b) 12 hr

(c) 1 min

(d) 1 min

Explanation: Option (b) is correct:The hour hand of a watch completes one revolution in 12 hours, so its time period is 12 hours.

16. Which of the following quantities is doubled on doubling the amplitude of a harmonic oscillator?

(a) Total energy

(b) Kinetic energy

(c) Maximum velocity

(d) PE

Explanation: Option (a) is correct:The total energy of a harmonic oscillator is proportional to the square of the amplitude. Doubling the amplitude increases the total energy by a factor of 2^2 = 4.

17. Which of the following characteristics must remain constant for undamped oscillations of the particle?

(a) Acceleration

(b) Phase

(c) Amplitude

(d) Velocity

Explanation: Option (b) is correct: In undamped oscillations, while the amplitude can remain constant, the phase is a characteristic that defines the position and velocity of the oscillating particle at any given time. It does not change unless the system is affected by external forces.

18. Time period of the simple pendulum at Karachi and at Murree are related as:

(a) TK < TM

(b) TK > TM

(c) TK = TM

(d) Can’t say anything

Explanation: Option (d) is correct:The time period of a simple pendulum depends on the acceleration due to gravity. Since the acceleration due to gravity varies slightly with location, the time periods at Karachi and Murree may not be exactly the same.

19. A simple pendulum is oscillating in a lift. If the lift starts moving upwards with uniform acceleration, the period will:

(a) Remain same  

(b) Be shorter

(c) Be longer

(d) Can’t say anything

Explanation: Option (b) is correct: When a lift moves upwards with uniform acceleration, the effective gravitational acceleration acting on the pendulum increases. This causes the time period of the pendulum to decrease.

20. In order to double the period of a simple pendulum:

(a) Its length should be doubled

(b) Its length should be quadrupled

(c) The mass of its bob should be doubled

(d) The mass of its bob should be quadrupled

Explanation: Option (b) is correct: The time period of a simple pendulum is proportional to the square root of its length. To double the period, the length must be increased by a factor of 2^2 = 4.