n identical cells, each of emf E and internal resistance r, are connected in series to form a closed circuit. If one cell is reversed, what is the current in the circuit?

Amount of electricity required to pass through the ${H_2}O$ voltmeter so as to liberate $11.2\,\,litre$ of hydrogen will be

A copper voltmeter and a silver voltmeter are connected in series in a circuit. The rate of the increase in the weight of the cathode in the two voltmeters will be in the ratio of

When a battery is connected to the resistance of $10\,\Omega$ the current in the circuit is $0.12A$. The same battery gives $0.07A$ current with $20\,\Omega$. Calculate emf and internal resistance of the battery.

A battery of emf $E$ has an internal resistance $r$. A variable resistance $R$ is connected to the terminals of the battery. A current $i$ is drawn from the battery. $V$ is the terminal potential difference. If $R$ alone is gradually reduced to zero, which of the following best describes $i$ and $V$ ?

A constant voltage is applied between two ends of a metallic wire. If the wire is replaced by another wire of same material, half the length and doubled the radius, the rate of heat developed in the wire will be:

If ${\rm{1}}\,{\rm{ A}}$ current is passed through ${\rm{C}}\,{\rm{u}}\,{\rm{S}}\,{{\rm{O}}_4}$ solution for ${\rm{10}}\,\,{\rm{s}}$, the number of copper atoms deposited at the cathode will be

What is the main component of the plant cell wall?

$n$ identical cells, each of emf $E$ and internal resistance $r$, are connected in series a cell $A$ is joined with reverse polarity. The potential difference across each cell, except $A$ is

What determines the emf between the two metals placed in an electrolyte?

A battery of emf 10V and internal resistance 3Ω is connected to a resistor. If the current in the circuit is 0.5A, what is the terminal voltage of the battery when the circuit is closed?