An ammeter with a zero error is connected in series with a silver voltameter. The ammeter reads $0.54 \ A$. In $1 \ hour$, $2.0124 \ g$ of silver is deposited. If the electrochemical equivalent of silver is $1.118 \times 10^{-3} \ g \ C^{-1}$, then the error in the ammeter reading is ............... $A$.

The charge flowing through a resistance $R$ varies with time according to $Q = at - bt^2$. The total heat produced in $R$ is: (assume that the direction of current is not reversed)

In Circuit-$1$ and Circuit-$2$ shown in the figures,$R_1=1 \Omega, R_2=2 \Omega$ and $R_3=3 \Omega$. $P_1$ and $P_2$ are the power dissipations in Circuit-$1$ and Circuit-$2$ when the switches $S_1$ and $S_2$ are in open conditions,respectively. $Q_1$ and $Q_2$ are the power dissipations in Circuit-$1$ and Circuit-$2$ when the switches $S_1$ and $S_2$ are in closed conditions,respectively. Which of the following statement$(s)$ is(are) correct?
$(A)$ When a voltage source of $6 V$ is connected across $A$ and $B$ in both circuits,$P_2 > P_1$.
$(B)$ When a constant current source of $2 A$ is connected across $A$ and $B$ in both circuits,$P_1 > P_2$.
$(C)$ When a voltage source of $6 V$ is connected across $A$ and $B$ in Circuit-$1$,$Q_1 > P_1$.
$(D)$ When a constant current source of $2 A$ is connected across $A$ and $B$ in both circuits,$Q_1 > Q_2$.

$A$ coil of wire of resistance $50\,\Omega$ is embedded in a block of ice. If a potential difference of $210\,V$ is applied across the coil,the amount of ice melted per second will be

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 ................ $kJ$.

The direction of current in an iron-copper thermocouple is