The following four wires are made of the same material. Which of these will have the largest extension when the same tension is applied?

$A$ rod of length $L$ and radius $r$ is held between two rigid walls so that it is not allowed to expand. If its temperature is increased,then the force developed in it is proportional to .........

$A$ $500 \,g$ ball is attached to one end of an aluminum wire of area of cross-section $0.5 \,mm^2$ and an unstretched length of $1.4 \,m$. The other end of the wire is fixed to the top of a vertical pole. The ball rotates about the pole in a horizontal plane such that the angle between the wire and the horizontal is $30^{\circ}$. The increase in the length of the wire is . . . . . . $mm$. (Young's modulus of aluminum $= 0.7 \times 10^{11} \,N/m^2$ and acceleration due to gravity $= 10 \,m/s^2$)

$A$ metal rod of length $L$ and cross-sectional area $A$ is heated through $T^{\circ} C$. What is the force required to prevent the expansion of the rod lengthwise? ($Y=$ Young's modulus of the material of the rod,$\alpha=$ coefficient of linear expansion of the rod.)

As shown in the figure,in an experiment to determine Young's modulus of a wire,the extension-load curve is plotted. The curve is a straight line passing through the origin and makes an angle of $45^{\circ}$ with the load axis. The length of the wire is $62.8\,cm$ and its diameter is $4\,mm$. The Young's modulus is found to be $x \times 10^4\,N/m^2$. The value of $x$ is

$A$ wire of length $100 \ cm$ and area of cross-section $2 \ mm^2$ is stretched by two forces of each $440 \ N$ applied at the ends of the wire in opposite directions along the length of the wire. If the elongation of the wire is $2 \ mm$,the Young's modulus of the material of the wire is: