Two separate wires A and B are stretched by 2 mm and 4 mm… | JEE Main 2021 (18 Mar, Shift 1)

Q22JEE Main 2021 · 18 MAR · SHIFT 1Medium

Young's Modulus & Elongation

Two separate wires A and B are stretched by 2 mm and 4 mm respectively, when they are subjected to a force of 2 N. Assume that both the wires are made up of same material and the radius of wire B is 4 times that of the radius of wire A. The length of the wires A and B are in the ratio of a: b. Then a/b can be expressed as 1/x where x is _________.

Numerical answer type. Work it out, then open the answer.

Show answer and solution

Answer: 32

$\Delta l = \frac{FL}{\pi r^2 Y}$ , so with same $F$ and $Y$ : $L \propto \Delta l \, r^2$
$\frac{L_A}{L_B} = \frac{2}{4} \times \left(\frac{r_A}{4r_A}\right)^2 = \frac{1}{2} \times \frac{1}{16} = \frac{1}{32}$
So $x = 32$ .

Report a mistake

More questions on Young's Modulus & Elongation

A wire of length L, area of cross section A is hanging from a fixed support. The length…NEET 2020 (Phase 1)
Two rods of same material and volume having circular cross-section are subjected to…MHT CET 2020 (16 Oct, Shift 1)
A wire of length L and radius r is rigidly fixed at one end. On stretching the other end…MHT CET 2019 (3 May, Shift 1)
Young's moduli of two wires A and B are in the ratio 7: 4. Wire A is 2 m long and has…JEE Main 2019 (8 Apr, Shift 2)
Two wires are made of the same material and have the same volume. The first wire has…NEET 2018
The Young's modulus of steel is twice that of brass. Two wires of same length and of same…NEET 2015 (AIPMT)
Copper of fixed volume V is drawn into wire of length l. When this wire is subjected to a…NEET 2014 (AIPMT)
The following four wires are made of the same material. Which of these will have the…NEET 2013

Young's Modulus & Elongation question from JEE Main 2021 (18 Mar, Shift 1)

More questions on Young's Modulus & Elongation