The Young's modulus of a wire is $Y$. If the energy per unit volume is $E$,then the strain will be

$A$ copper wire of length $4.0 \, m$ and area of cross-section $1.2 \, cm^2$ is stretched with a force of $4.8 \times 10^3 \, N$. If Young's modulus for copper is $1.2 \times 10^{11} \, N/m^2$,the increase in the length of the wire will be:

$A$ metallic rod $1 \, cm$ long with a square cross-section is heated through $1^{\circ} C$. If Young's modulus of elasticity of the metal is $E$ and the mean coefficient of linear expansion is $\alpha$ per degree Celsius,then the compressional force required to prevent the rod from expanding along its length is: (Neglect the change of cross-sectional area)

$A$ wire of length $L$ and radius $r$ is clamped at one end. If its other end is pulled by a force $F$,its length increases by $l$. If the radius of the wire and the applied force both are reduced to half of their original values keeping original length constant,the increase in length will become.

Two wires of the same material have lengths in the ratio $1:2$ and diameters in the ratio $2:1$. If they are stretched by forces $F_A$ and $F_B$ respectively to produce the same extension,then the ratio $\frac{F_A}{F_B}$ is:

What is Young's modulus? Explain it,and provide its unit and dimensional formula.