Consider the circuit given here. The potential difference $V_{BC}$ between the points $B$ and $C$ is (in $V$)

$A$ conductor is made of an isotropic material and has the shape of a truncated cone. $A$ battery of constant emf is connected across it and its left end is earthed as shown in the figure. If at a section distant $x$ from the left end, electric field intensity, potential, and the rate of generation of heat per unit length are $E, V$, and $H$ respectively, which of the following graphs is/are correct?

If two wires having resistance $R$ and $2R$ are joined in series and then in parallel,what is the ratio of heat generated in these two situations,assuming the same voltage is applied?

Two electric bulbs marked $40\,W, 220\,V$ and $60\,W, 220\,V$ are connected in series across a $220\,V$ supply,resulting in an effective power $P_1$. When they are connected in parallel across the same $220\,V$ supply,the effective power is $P_2$. The ratio $\frac{P_1}{P_2}$ is:

Electroplating does not help in

$A$ battery consists of a variable number $n$ of identical cells (each having electromotive force $\varepsilon$ and internal resistance $r$) which are connected in series. The terminals of the battery are short-circuited and the current $I$ is measured. Which of the graphs shows the correct relationship between $I$ and $n\,?$