For the tangential stress on the cross-section $PQRS$ to be maximum,$\theta = $ ....... $^o$

The cross-sectional areas of steel and brass wires are $0.1 \,cm^2$ and $0.2 \,cm^2$ respectively. If the same stress is produced in both by a weight $W$,what is the ratio of the tensions $T_1/T_2$?

Match the details of Column-$II$ with the given information in Column-$I$ appropriately.

Column-$I$	Column-$II$
$(a)$ Stress is proportional to strain.	$(i)$ Elastic limit
$(b)$ When the load on the wire is removed, the body regains its original dimension.	$(ii)$ Limit of proportionality
	$(iii)$ Plastic deformation

$A$ wire can be broken by applying a load of $20 \, kg$ weight. The force required to break the wire of twice the diameter is .......... $kg \, wt$.

Two wires as shown in the figure below,made of steel,have a breaking stress of $12 \times 10^8 \text{ N/m}^2$. The area of cross-section of the upper wire is $0.008 \text{ cm}^2$ and that of the lower wire is $0.004 \text{ cm}^2$. The maximum mass that can be added to the pan without breaking any wire is . . . . . . kg. (Take $g = 10 \text{ m/s}^2$)

Pressure and stress have the same unit (and dimension),although they are not the same physical quantity. Why?