Two bulbs of $500\, W$ and $200\, W$ are manufactured to operate on a $220\, V$ line. What is the ratio of heat produced in the $500\, W$ bulb to the $200\, W$ bulb when they are connected in parallel,and when they are connected in series?

Three wires of copper,iron,and nickel are joined to form three junctions as shown in the figure. When the temperature of junction $1$ is kept at $50\,^{\circ}\text{C}$ with the other two junctions at $0\,^{\circ}\text{C}$,the sensitive galvanometer gives a deflection of $14$ divisions. When the temperature of junction $3$ is kept at $50\,^{\circ}\text{C}$,with the other two junctions at $0\,^{\circ}\text{C}$,the galvanometer gives a deflection of $11$ divisions. Then the deflection given by the galvanometer,when the temperature of junction $2$ is kept at $50\,^{\circ}\text{C}$,with the other two junctions at $0\,^{\circ}\text{C}$,will be (in $div$)

If a battery of voltage $V$ is connected across terminals $I$ of the black box shown in the figure,an ideal voltmeter connected to terminals $II$ gives a reading of $V/2$. While if the battery is connected to terminals $II$,a voltmeter across terminals $I$ reads $V$. The black box may contain:

Which of the following graphs represents the variation of power loss $P$ in the external load with external resistance $R$?

The thermo emf of a hypothetical thermocouple varies with the temperature $\theta$ of the hot junction as $E = a\theta + b\theta^2$ in volts,where the ratio $a/b$ is $700^{\circ}C$. If the cold junction is kept at $0^{\circ}C$,then the neutral temperature is:

$A$ copper voltameter is connected in series with a heater coil of resistance $0.1\,\Omega$. $A$ steady current flows in the circuit for $20$ minutes and a mass of $0.99\,g$ of copper is deposited at the cathode. If the electrochemical equivalent of copper is $0.00033\,g/C$, then the heat generated in the coil is ............... $J$.