An electric kettle has two coils. When one coil is switched on,the tea gets heated in $10 \, \text{min}$. When the other coil is switched on,the same amount of tea gets heated in $40 \, \text{min}$. If both coils are connected in parallel,how long will it take to heat the same amount of tea (in $, \text{min}$)?

In the circuit shown in the figure,the capacitor $C$ is initially uncharged and the key $K$ is open. In this condition,a current of $1 \,A$ flows through the $1 \,\Omega$ resistor. The key is closed at time $t=t_0$. Which of the following statement(s) is(are) correct?

[Given: $e^{-1}=0.36$]
$(A)$ The value of the resistance $R$ is $3 \,\Omega$.
$(B)$ The current through the $3 \,\Omega$ resistor (connected in parallel to the $1 \,\Omega$ and $R$ branches) is $2 \,A$ when $K$ is open.
$(C)$ At $t=t_0+7.2 \,\mu s$,the current in the capacitor branch is $0.6 \,A$.
$(D)$ For $t < \infty$,the charge on the capacitor is $12 \,\mu C$.

Two resistors with resistances $R_1$ and $R_2$ are connected in series and two capacitors with capacitances $C_1$ and $C_2$ are also connected in series. These two systems are connected to a battery of $EMF$ $\varepsilon$ as shown in the figure. The potential difference between points $a$ and $b$ is zero in the steady state if:

In the circuit shown here,$E_1 = E_2 = E_3 = 2 \, V$ and $R_1 = R_2 = 4 \, \Omega$. The current flowing between points $A$ and $B$ through battery $E_2$ is

In a silver voltameter, $2.89 \ g$ of silver is deposited in $10 \ minutes$. The heat produced in a $20 \ \Omega$ resistor for the same time will be ................ $kJ$.

When current is passed in an antimony-bismuth couple,then: