Question

A rectangular frame is to be suspended symmetrically by two strings of equal length on two supports as shown in the figure. It can be done in one of the following three ways
The tension in the strings will be

• A. the same in all cases
• B. least in (i)
• C. least in (ii)
• D. least in (iii)

Answer 1

Answer: (C)

Let $M$ be the mass of rectangular frame and $\theta$ be the angle which the tension $T$ in the string makes with the horizontal as shown in the figure.
$\therefore$ $2Tsin\theta$ $=Mg$

or $T=\frac{Mg}{2sin\theta }$
or $T\propto \frac{1}{sin\theta }$
$T$ is least if sin $\theta$ has maximum value i.e., $sin\theta =1=sin90^{\circ }$.
Thus option is correct.