Calculate the current (in $mA$) required to deposit $0.195 \ g$ of platinum metal in $5.0 \ hours$ from a solution of $[PtCl_6]^{2-}$ : (atomic weight: $Pt = 195$)

$A$ magnet of magnetic moment $50\,\hat{i}\,\text{A}\,\text{m}^2$ is placed along the $x$-axis in a magnetic field $\vec{B} = (0.5\,\hat{i} + 3.0\hat{j})\,\text{T}$. The torque acting on the magnet is:

If $l, m, n$ are in arithmetic progression,then the straight line $lx + my + n = 0$ will always pass through the point:

If $ax^2+2hxy+by^2+2gx+2fy+c=0$ represents a pair of parallel lines,then $\sqrt{\frac{g^2-ac}{f^2-bc}}$ is equal to

Copper sulphate is prepared by blowing a current of air through copper scrap and dilute $H_{2}SO_{4}$. Dilute $HNO_{3}$ is also added:

The network shown in the figure is a part of a complete circuit. If at a certain instant the current $i$ is $5 \, A$ and is decreasing at the rate of $10^3 \, A/s$,then $V_A - V_B$ is....... $V$.