$A$ wire of resistance $R$ is bent in the form of a circular loop. Two points on the circle separated by a quarter circumference are connected to a battery of emf $E$ and negligible internal resistance. The heat generated in the wire per second is

$A$ uniform metallic wire carries a current of $2\,A$ when a $3.4\,V$ battery is connected across it. The mass of the uniform metallic wire is $8.92 \times 10^{-3}\,kg$,its density is $8.92 \times 10^3\,kg/m^3$,and its resistivity is $1.7 \times 10^{-8}\,\Omega\cdot m$. The length of the wire is $l = \dots\dots\dots\dots\,m$.

Model a torch battery of length $l$ to be made up of a thin cylindrical bar of radius $a$ and a concentric thin cylindrical shell of radius $b$,filled in between with an electrolyte of resistivity $\rho$ (see figure). If the battery is connected to a resistance of value $R$,the maximum Joule heating in $R$ will take place for:

In the figure shown,battery $1$ has $emf = 6\, V$ and internal resistance $= 1\, \Omega$. Battery $2$ has $emf = 2\, V$ and internal resistance $= 3\, \Omega$. The wires have negligible resistance. What is the potential difference across the terminals of battery $2$ (in $, V$)?

The ammeter $A$ reads $2\, A$ and the voltmeter $V$ reads $20\, V$. The value of resistance $R$ is (Assuming finite resistances of ammeter and voltmeter).

In the given circuit,the voltmeter records $5 \, V$. The resistance of the voltmeter in $ohms$ is