Mark the wrong statement.

$Dyne/cm^2$ is not a unit of

Copper has a face-centered cubic $(fcc)$ lattice with an interatomic spacing equal to $2.54 \ \mathring{A}$. The value of the lattice constant for this lattice is .... $\mathring{A}$ $[AIPMT \ 2005]$

Match the following:

Column-$I$	Column-$II$
$(A)$ Shear modulus	$(I)$ Resistance to change in volume
$(B)$ Shearing stress	$(II)$ Proportionality constant
$(C)$ Elastic fatigue	$(III)$ Tangential stress
$(D)$ Modulus of elasticity	$(IV)$ Temporary loss of elastic property
	$(V)$ Resistance to change against deformation force

The correct match is:

$A$ substance breaks down by a stress of $10^6 \ N/m^2$. If the density of the material of the wire is $3 \times 10^3 \ kg/m^3$,then the length of the wire of the substance which will break under its own weight when suspended vertically,is ......... $m$.

Each of three blocks $P$,$Q$ and $R$ shown in the figure has a mass of $3 \,kg$. Each of the wires $A$ and $B$ has a cross-sectional area of $0.005 \,cm^2$ and a Young's modulus of $2 \times 10^{11} \,N \,m^{-2}$. Neglecting friction,the longitudinal strain on wire $B$ is . . . . . . $\times 10^{-4}$. (Take $g=10 \,m/s^2$)