# Physics Practical Class 11 - Using a simple pendulum, plot its L-T2 graph and use it to find the effective length of secondâ€™s pendulum. Viva Questions with Answers

1) If a particle moves with simple harmonic motion, then its periodic time can be defined as the time taken by the particle to complete one oscillation. Is it true or false?

The above statement is true because, according to the definition of the time period, periodic time is defined as the time taken by a particle to complete one oscillation while moving in simple harmonic motion.

2) Between speed and acceleration, which variable will become zero at the extreme position in SHM?

The body comes to instantaneous rest at the extreme position in SHM, and hence, according to the force eqn: F = -kx, the acceleration and force become maximum at this point. So, the speed at an extreme position becomes zero, and acceleration becomes maximum.

3) What is a simple pendulum?

A device suspended from fixed support where its point mass is attached to a light string that cannot stretch itself, no matter how much you pull (inextensible), is known as a simple pendulum. The mean position of a simple pendulum is the vertical line passing through the fixed support.

4) What is simple harmonic motion?

A repetitive back and forth movement of an object through an equilibrium position is known as simple harmonic motion. The movement should be such that the extreme displacement on one side of the centre position is equal to the extreme displacement on the other side. To complete each vibration, the time interval will be the same.

5) What do you mean by standing wave?

The combination of two waves obtained due to interference, having the same amplitude and frequency and moving in opposite directions is known as a standing wave. The standing wave is also identified as the stationary wave.

6) What is the relationship between time period and frequency?

(f = 1/T) can be given as the relationship between time period and frequency, where f= frequency and T = Time period.

7) If a particle is moving with simple harmonic motion, then its acceleration will be inversely proportional to its displacement from the mean position. Is it true or false?

The above statement is false because if a particle moves with simple harmonic motion, then its acceleration is directly proportional to its displacement from the mean position.

8) Define the amplitude of a simple pendulum.

The distance travelled by the pendulum from its equilibrium position to one side is known as the amplitude of a simple pendulum.

9) What is the phase difference between acceleration and velocity in simple harmonic motion?

The phase difference between acceleration and velocity in simple harmonic motion is generally Ï€/2.

10) In a uniform circular motion, the angular speed of a body is equivalent to the angular frequency of SHM of its projection. Is it true or false?

The statement is true.

Let us assume â€˜wâ€™ be the angular speed of the body starting from rest (x-axis), and it has covered an angle of â€˜wtâ€™ at any time â€˜tâ€™.

Now, on the x-axis, the projection will be given by: x = Asin(wt).

Therefore, this shows that the angular frequency of SHM will be the same as the angular speed.