Topic 3: Hooke’s Law

Hooke’s Law

Hooke’s law states that within the elastic limit, the stress produced in a material is directly proportional to the strain.

Statement of Hooke’s Law

Within elastic limit:

Stress ∝ Strain

Or,

Stress = k × Strain

where k is a constant known as the modulus of elasticity.

Importance of Hooke’s Law

Valid only up to elastic limit
Explains linear stress–strain relation
Used to define elastic moduli

Graphical Representation

Stress–strain graph is a straight line passing through origin within elastic limit.

Q1. Hooke’s law is valid up to:
A) Breaking point
B) Elastic limit
C) Yield point
D) Plastic limit

Answer: B


Q2. According to Hooke’s law:
A) Stress is inversely proportional to strain
B) Stress is directly proportional to strain
C) Stress equals force
D) Stress equals strain

Answer: B


Q3. Stress–strain graph within elastic limit is:
A) Curved
B) Horizontal
C) Straight line
D) Vertical

Answer: C


Q4. The constant of proportionality in Hooke’s law is called:
A) Force constant
B) Elastic limit
C) Modulus of elasticity
D) Pressure constant

Answer: C


Q5. Hooke’s law fails beyond:
A) Elastic limit
B) Proportional limit
C) Breaking point
D) Yield point

Answer: A

Chapter 6: Mechanical Properties of Solids

Topic 3: Hooke’s Law – Quick Revision

Statement

Within elastic limit, stress is directly proportional to strain.

Formula

Stress = k × Strain

Key Points

Valid only within elastic limit
k = modulus of elasticity
Stress–strain graph is linear

Exam Focus (MHT-CET)

Direct MCQs are frequently asked on statement, validity and graph of Hooke’s law.

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