Q. No.A rigid bar of mass M is supported symmetrically by three wires each of length l . Those at each end are of copper and the middle one is of iron. The ratio of their diameters, if each is to have the same tension, is equal to
1. \(Y_{\text {copper }} / Y_{\text {iron }} \)
2. \(\sqrt{\frac{Y_{\text {iron }}}{Y_{\text {copper }}}} \)
3. \(\frac{Y_{\text {tron }}^2}{Y_{\text {copper }}^2} \)
4. \(\frac{Y_{\text {iron }}}{Y_{\text {copper }}}\)
1. \(Y_{\text {copper }} / Y_{\text {iron }} \)
2. \(\sqrt{\frac{Y_{\text {iron }}}{Y_{\text {copper }}}} \)
3. \(\frac{Y_{\text {tron }}^2}{Y_{\text {copper }}^2} \)
4. \(\frac{Y_{\text {iron }}}{Y_{\text {copper }}}\)
Subtopic: Young's modulus |
93%
Level 1: 80%+
Please attempt this question first.
Hints
A steel wire with a cross-sectional area of \(3\times 10^{-6} \) m2 can withstand a maximum strain of \(10^{-3}.\) Young's modulus of steel is \(Y=2\times 10^{11} \) N/m2. The maximum mass that the wire can hold is:
( take \(g=10\) m/s2)
1. \(50\) kg
2. \(60\) kg
3. \(70\) kg
4. \(80\) kg
( take \(g=10\) m/s2)
1. \(50\) kg
2. \(60\) kg
3. \(70\) kg
4. \(80\) kg
Subtopic: Young's modulus |
92%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
A wire of length \(L\) and radius \(r \) is clamped rigidly at one end. When the other end of the wire is pulled by a force \(F,\) its length increases by \(5~\text{cm}. \) Another wire of the same material of length \(4L\) and radius \(4r \) is pulled by a force \(4F \) under the same conditions. The increase in length of this wire is:
1. \(3~\text{cm}\)
2. \(5~\text{cm}\)
3. \(10~\text{cm}\)
4. \(6~\text{cm}\)
1. \(3~\text{cm}\)
2. \(5~\text{cm}\)
3. \(10~\text{cm}\)
4. \(6~\text{cm}\)
Subtopic: Young's modulus |
91%
Level 1: 80%+
JEE
Please attempt this question first.
Hints
Please attempt this question first.
The dimensions of stress, strain, and Young's modulus of elasticity are, respectively:
| 1. | \(\left[MT^{-2}\right], ~[L]~,~\left[ML^{-1}T^{-2}\right]\) |
| 2. | \(\left[ML^{-1}T^{-2}\right],~\left[M^0L^{0}T^{0}\right],~\left[ML^{-1}T^{-2}\right]\) |
| 3. | \(\left[M^0L^0T^0\right],~[L]~,~\left[ML^{-1}T^{-2}\right]\) |
| 4. | \(\left[MLT^{-2}\right]~,\left[ML^2T^{-2}\right],~\left[MT^{-2}\right]\) |
Subtopic: Young's modulus |
90%
Level 1: 80%+
Hints
The elongation of a wire on the surface of the Earth is \(10^{-4}\) m. The same wire, of the same dimensions, elongates by \( 6 \times 10^{-5} \) m on another planet. The acceleration due to gravity on the planet will be:
(take acceleration due to gravity on the surface of the Earth as \(10\) m s-2)
1. \(5\) ms-2
2. \(6\) ms-2
3. \(7\) ms-2
4. \(8\) ms-2
(take acceleration due to gravity on the surface of the Earth as \(10\) m s-2)
1. \(5\) ms-2
2. \(6\) ms-2
3. \(7\) ms-2
4. \(8\) ms-2
Subtopic: Young's modulus |
90%
Level 1: 80%+
JEE
Please attempt this question first.
Hints
Please attempt this question first.
The Young's modulus of a wire of radius \(R\) and length \(L\) is \(Y \mathrm{~N} / \mathrm{m}^2\). If radius and length are changed to \(2 R\) and \(4L\) respectively, then its Young's modulus will be:
1. \(Y\)
2. \(2Y\)
3. \(\frac{Y}{2}\)
4. \(5 Y\)
1. \(Y\)
2. \(2Y\)
3. \(\frac{Y}{2}\)
4. \(5 Y\)
Subtopic: Young's modulus |
88%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
A steel wire has a proportional limit of \(8 \times 10^8~\text{N/m}^2\) and a Young’s modulus of \(2 \times 10^{11}~\text{N/m}^2.\) If the wire is \(1~\text{m}\) long, what is the maximum elongation it can undergo without exceeding the proportional limit?
| 1. | \(2~\text{mm}\) | 2. | \(4~\text{mm}\) |
| 3. | \(1~\text{mm}\) | 4. | \(8~\text{mm}\) |
Subtopic: Stress - Strain Curve | Young's modulus |
88%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
A uniform heavy rod of mass \(20\) kg, cross-sectional area of \(0.4\) m2 and length of \(20\) m is hanging from a fixed support. Neglecting the lateral contraction, the elongation in the rod due to its own weight is:
(Given: Young’s modulus \(Y=2\times 10^{11}\) N-m–2 and \(g=10~\text{ms}^{–2 }\) )
1. \(12\times 10^{-9}\) m
2. \(30\times 10^{-9}\) m
3. \(25\times 10^{-9}\) m
4. \(35\times 10^{-9}\) m
(Given: Young’s modulus \(Y=2\times 10^{11}\) N-m–2 and \(g=10~\text{ms}^{–2 }\) )
1. \(12\times 10^{-9}\) m
2. \(30\times 10^{-9}\) m
3. \(25\times 10^{-9}\) m
4. \(35\times 10^{-9}\) m
Subtopic: Young's modulus |
88%
Level 1: 80%+
JEE
Please attempt this question first.
Hints
Please attempt this question first.
The equivalent of spring constant \(k\) for a wire of length \(L\), cross-sectional area, and Young's modulus \(Y\)is:
1. \(\frac{Y L}{A} \)
2. \(\frac{YA}{L}\)
3. \(\frac{A L}{Y}\)
4. \( YAL \)
1. \(\frac{Y L}{A} \)
2. \(\frac{YA}{L}\)
3. \(\frac{A L}{Y}\)
4. \( YAL \)
Subtopic: Young's modulus |
88%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
A vertical wire \(5~\text m\) long and \(8\times 10^{-3}~\text{cm}^2\) cross-sectional area has Young's modulus \(=200~\text {GPa}\) (as shown in the figure). What will be the extension in its length, when a \(2~\text{kg}\) object is fastened to its free end?
1. \(0.625~\text{mm}\)
2. \(0.65~\text{mm}\)
3. \(0.672~\text{mm}\)
4. \(0.72~\text{mm}\)
1. \(0.625~\text{mm}\)
2. \(0.65~\text{mm}\)
3. \(0.672~\text{mm}\)
4. \(0.72~\text{mm}\)
Subtopic: Young's modulus |
87%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
© 2026 GoodEd Technologies Pvt. Ltd.