JEE PHYSICS MCQ: MECHANICAL PROPERTIES OF SOLIDS

1 Easy

1 of 1

Application +4 | -1

A wire extends by

\mathrm{1 mm}

when a force is applied. Double the force is applied to another wire of same material and length but half the radius of cross-section. The elongation of the wire in mm will be

View answer and explanation

Correct option: A

\mathrm{8}

Option A (8) is correct because the elongation is inversely proportional to the area (or square of the radius) and directly proportional to the force. Doubling the force and halving the radius results in 8 times the elongation.

More Questions from MECHANICAL PROPERTIES OF SOLIDS

Practice All Chapter MCQs →

A wire is stretched under a force. If the wire suddenly snaps the temperature of the wire The increases in length is

l

of a wire of length

L

by the longitudinal stress. Then the stress is proportional to A steel wire of length

l

and cross sectional area

\mathrm{A}

is stretched by

1 \mathrm{~cm}

under a given load. When the same load is applied to another steel wire of double its length and half of its cross section area, the amount of stretching (extension) is Assertion: From the relation

Y=\frac{F l}{A \Delta l},

we can say that, if length of a wire is doubled, its Young's modulus of elasticity will also becomes two times.

Reason: Modulus of elasticity is a material property. A wire can be broken by applying a load of 200 N. The force required to break another wire of the same length and same material, but double in diameter, is Assertion(A): If radius of cylindrical wire is doubled, then this wire can bear four times stress.

Reason(R): By doubling the radius, area of cross-section will become four times.