Practical Exam
Young’s Modulus – Viva Voice Question With Answer
For: Science Class 11 | Physics

Q.1: Define elasticity.
Ans. Property of materials to regain their original length, volume or shape after the deforming force has been removed.

Q.2: State Hooke’s Law.
Ans. “If the deforming force is not greater than elastic limit, the strain is directly proportional to the
stress.” -> Stress α Strain  or (Stress / Strain) = E
Here constant ‘E’ is called “MODULUS OF ELASTICIT”.

Q.3: Define YOUNG’S MODULUS(Y).
Ans. The ratio of longitudinal stress to the linear strain -> ( Longitudinal Stress / Linear Strain)  = Y

Q.4: What is elastic limited?
Ans. The maximum value of stress beyond which stress is not proportional to strain. (Beyond elastic limit strain is rapid).

Q.5: Define STRESS.
Ans. The restoring force per unit area set up inside the body which is under the influence of
deforming force. – > Stress (inside the body) = deforming force (externally applied)

Q.6: Define Strain.
Ans. The ratio of change in length (L), volume (V) or shape to the original length (L) volume (V) or
shape.
l / L = longitudinal strain
v/ V = cubical strain

Q.7: What are the units of:
(a) Stress (b) Strain (c) Young’s modulus
Ans. (a) Newton/meter² or dynes/cm²
(b) No units since if the ratio between the similar quantities
(c) N/m² or dynes/cm²

Q.8: What is the function of second wire?
Ans. To eliminate the error due to change in temperature.

Q.9: Which one is more elastic, foam or iron?
Ans. Iron, because iron can regain its original shape or length more easily than foam.

Q.10: Gases and liquids have elasticity or not?
Ans. Yes, they have.