The terminal voltage $V$ across a battery of $emf$ $E$ and internal resistance $r$ can be:

$A$ battery is charged by a $15\,V$ battery for $8\,h$ at a current of $10\,A$. When this battery discharges, it provides a current of $5\,A$ for $15\,h$. The average terminal voltage during discharge is $14\,V$. What is the $watt-hour$ efficiency of this battery in $\%$?

$A$ certain charge liberates $0.8\, gm$ of ${O_2}$. The same charge will liberate how many $gm$ of silver?

Total $emf$ produced in a thermocouple does not depend on

$A$ thermocouple is made from two metals,Antimony and Bismuth. If one junction of the couple is kept hot and the other is kept cold,then,an electric current will

The two ends of a conductor are connected to a cell having an $e.m.f. \ E$ and some internal resistance. Starting from the midpoint $P$ of the conductor,moving in the direction of the current,and returning to point $P$,which of the following graphs best represents the potential $V$ versus the distance $x$ covered along the path?