Question

Assertion (A): Steel is more elastic than rubber.

Reason (R) : Under a given deforming force, steel is deformed less than rubber.

A) Both Assertion and Reason are true and the reason is correct explanation of the assertion
B)Both Assertion and Reason are true, but reason is not correct explanation of the assertion
C) Assertion is true, but the reason is false
D) Assertion is false, but the reason is true

• A. A
• B. B
• C. C
• D. D

Answer 1

The correct option is A. A: Both Assertion and Reason are true and the reason is correct explanation of the assertion.

More elastic the material, the higher the Young's Modulus.
Young's Modulus of Steel = 200 GPa
Young's Modulus of Rubber = 0.01-0.1 GPa
Young's Modulus of Steel is much higher than Rubber, so steel is more elastic than rubber.
Y = FL/Al
Y - Young's Modulus
L - Actual Length
A - Cross Section Area
l - Elongation
l = FL/AY
keeping F, L, A constant
l is inversely proportional to Y
Hence, the Higher Young's Modulus lesser the deformation (for Different Materials).