$A$ thin liquid film formed between a $U$-shaped wire and a light slider supports a weight of $1.5 \times 10^{-2} \ N$ (see figure). The length of the slider is $30 \ cm$ and its weight is negligible. The surface tension of the liquid film is (in $N/m$)

In the arrangement shown in the figure,the masses of blocks $B$ and $A$ are $2m$ and $m$ respectively. The surface between $B$ and the floor is smooth. Block $B$ is connected to block $C$ by means of a string-pulley system. If the whole system is released,find the minimum value of the mass of block $C$ so that block $A$ remains stationary with respect to $B$. The coefficient of friction between $A$ and $B$ is $\mu$.

If the lines $2x + 3y + 12 = 0$ and $x - y + k = 0$ are conjugate with respect to the parabola $y^2 = 8x$,then $k$ is equal to

In the circuit shown in the figure, what is the value of $I_1$ just after pressing the key $K$?

$A$ spring $40\,mm$ long is stretched by the application of a force. If $10\,N$ force is required to stretch the spring through $1\,mm$,then work done in stretching the spring through $40\,mm$ is ............. $J$.

The magnetic susceptibility of a paramagnetic material at $-73\,^{\circ}C$ is $0.0075$. What will be its value at $-173\,^{\circ}C$?