The Thomson coefficient of a conductor is $10 \mu V/K$. The two ends of the conductor are kept at $50^{\circ} C$ and $60^{\circ} C$,respectively. The amount of heat absorbed by the conductor when a charge of $10 C$ flows through it is:

$A$ coil takes $15\,min$ to boil a certain amount of water,and another coil takes $20\,min$ for the same process. What is the time taken to boil the same amount of water when both coils are connected in series?

$A$ certain amount of charge produces $0.8 \, g$ of $O_2$. How many grams of silver will the same amount of charge produce?

$A$ 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 ............... $J$.

Identify the correctness of the following statements:
$(1)$ The product of a volt and a coulomb is a joule.
$(2)$ The product of a volt and an ampere is a joule/second.
$(3)$ The product of a volt and a watt is a horsepower.
$(4)$ $A$ watt-hour can be measured in terms of an electron volt.

Two rods of copper $(Cu)$ and iron $(Fe)$ with the same cross-sectional area are joined at $S$ and a steady current $I$ flows through the rods as shown in the figure. Choose the most appropriate representation of charges accumulated near the junction $S$.