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1.

The breaking stress of a wire depends on:

1.	length of the wire
2.	applied force
3.	material of the wire
4.	area of the cross-section of the wire

2.

The length of an elastic string is \(a\) metre when the longitudinal tension is \(4\) N and \(b\) metre when the longitudinal tension is \(5\) N. The length of the string in metre when the longitudinal tension is \(9\) N will be:

1.	\(a-b\)	2.	\(5b-4a\)
3.	\(2b-\frac{1}{4}a\)	4.	\(4a-3b\)

3.

The stress-strain graphs for materials \(A\) and \(B\) are shown in the figure. Young’s modulus of material \(A\) is:
(the graphs are drawn to the same scale)
                       

1.	equal to material \(B\)
2.	less than material \(B\)
3.	greater than material \(B\)
4.	can't say

4.

Steel and copper wires of the same length and area are stretched by the same weight one after the other. Young's modulus of steel and copper are \(2\times10^{11} ~\text{N/m}^2\) and  \(1.2\times10^{11}~\text{N/m}^2.\) The ratio of increase in length is: 

1.	\(2 \over 5\)	2.	\(3 \over 5\)
3.	\(5 \over 4\)	4.	\(5 \over 2\)

5. The bulk modulus of rubber is \(9.8\times10^{8}~\text{N/m}^2\) To what depth a rubber ball be taken in a lake so that its volume is decreased by \(0.1\%\)?

1.	\(25\) m	2.	\(100\) m
3.	\(200\) m	4.	\(500\) m

6.

The increase in the length of a wire on stretching is \(0.04\)%. If Poisson's ratio for the material of wire is \(0.5,\) then the diameter of the wire will:

1.	decrease by \(0.02\)%.	2.	decrease by \(0.01\)%.
3.	decrease by \(0.04\)%.	4.	increase by \(0.03\)%.

7.

If \(E\) is the energy stored per unit volume in a wire having \(Y\) as Young's modulus of the material, then the stress applied is:
1. \(\sqrt{2EY}\)
2. \(2\sqrt{EY}\)
3. \(\frac{1}{2}\sqrt{EY}\)
4. \(\frac{3}{2}\sqrt{EY}\)

8.

A wire of length \(L,\) area of cross section \(A\) is hanging from a fixed support. The length of the wire changes to \({L}_1\) when mass \(M\) is suspended from its free end. The expression for Young's modulus is:

1.	\(\dfrac{{Mg(L}_1-{L)}}{{AL}}\)	2.	\(\dfrac{{MgL}}{{AL}_1}\)
3.	\(\dfrac{{MgL}}{{A(L}_1-{L})}\)	4.	\(\dfrac{{MgL}_1}{{AL}}\)

9. A steel ring of radius \(r\) and cross-section area \(A\) is fitted onto a wooden disc of radius \(R(R>r).\) If Young's modulus is \({E},\) then the force with which the steel ring is expanded is:

1.	\({AE} \frac{R}{r} \)	2.	\(A E \left(\frac{R-r}{r}\right)\)
3.	\(\frac{E}{A}\left(\frac{R-r}{A}\right)\)	4.	\(\frac{Er}{AR}\)

10.

Young’s modulus of steel is twice that of brass. Two wires of the same length and of the same area of cross-section, one of steel and another of brass, are suspended from the same roof. If we want the lower ends of the wires to be at the same level, then the weights added to the steel and brass wires must be in the ratio of:
1. \(1:2\)
2. \(2:1\)
3. \(4:1\)
4. \(1:1\)