# Physics Experiment's Viva Questions

Some Physics Experiment's Viva Questions

1. The Moment Bar Viva Questions and Answers Moment Bar
(i) What is the principle of the moment bar?

Ans: The principle of moment. That is, the algebraic sum of the moment of the forces acting on a rigid body is zero.

(ii) Why do you suspend the metre scale at the centre of gravity to find the weight of a body?

Ans: In order to make the moment of the weight of the scale about the point of suspension zero.

(iii) Can you find the relative density of a body using moment bar.

Ans: Yes

2. The Helical Spring Viva Questions and Answers

(i) Define stress

Ans: It is the normal force acting per unit area.

(ii) State Hookes law

Ans: Within elastic limits stress is proportional to the stain

(iii) What is spring constant?

Ans: F = -kx; where k is the spring constant. It is the force required to produce unit extension.

(iv) What are the conditions essential for the motion of a body to be simple harmonic?

Ans:
(a) acceleration is proportional to its distance from the fixed point
(b) acceleration is directed towards a fixed point

(v) What are the factors on which the period of vertical oscillations of a spring depend?

Ans:
(a) Directly proportional to the square root of the mass attached
(b) inversely proportional to the spring constant

(vi) What is the unit of spring constant?

Ans: Nm-1

(vii) Which is more elastic-steel wire or rubber wire of the same diameter and length?

Ans: Steel wire

(viii) What is the relation between load and extension?

(ix) What is the spring constant in terms of load (M) and extension (e)

Ans: K = Load / Extension = M/e kg/m = (M/e)gNm-1

3. The Friction Viva Questions

(i) What is meant by friction?
(ii) Explain limiting static friction.
(iii) Distinguish between static friction and dynamic friction.
(iv) Define coefficient of friction.
(v) What are the factors on which coefficient of friction depends?
(vi) What is rolling friction?
(vii) Why is friction considered a necessary evil?
(viii) Lubricants reduces friction, how?

4. The Young's Modulus Viva Questions

(i) Explain the term 'stress' and 'strain"?
(ii) Distinguish between stress and pressure.
(iii) What is meant by elastic limit?
(iv) State Hook's law.
(v) What is the modulus of elasticity?
(vi) What are the different moduli of elasticity?
(vii) Define Young's modulus of a substance.
(viii) What is the unit of modulus of elasticity?
(ix) Why do you use a micrometer or vernier instead of a metre scale to measure the increase in length of the wire?
(x) What is elastic hysteresis?

5. The Newton's Law of Cooling Viva Questions

(i) Name the different modes of transmission of heat.