In the circuit, the electric current through the battery is Ampere(s).

If $X,Y$ and $Z$ in figure are identical lamps, which of the following changes to the brightness of the lamps occur when switch $S$ is closed?

In the circuit shown in figure the heat produced in the $5 \mathrm{\Omega }$ resistor due to the current flowing through it is 10 cal/s .

The heat generated in the $4 \mathrm{\Omega }$ resistor is 

In the figure shown the power generated in $y$ is maximum when $y=5\Omega$. Then $R$ is 

A circuit is comprised of eight identical batteries and a resistor $R=0.8\mathrm{\Omega }$. Each battery has an $\mathrm{emf}$ of $1.0 \mathrm{V}$ and internal resistance of $0.2\Omega$. The voltage difference across any of the battery is

In the circuit shown the resistance of voltmeter is $10,000$ohm and that of ammeter is $20$ ohm. The ammeter reading is $0.10\mathrm{Amp}$ and voltmeter reading is $12$volt. Then $R$ is equal to