What is the magnitude of the electric charge on an electron?

The unit of electric potential difference is $.....$

Three resistors of $5 \, \Omega$,$10 \, \Omega$,and $15 \, \Omega$ are connected in series,and the combination is connected to a battery of $30 \, V$. An ammeter and a voltmeter are connected in the circuit. Draw a circuit diagram to connect all the devices in the correct order. What is the current flowing through the circuit and the potential difference across the $10 \, \Omega$ resistor?

What is the practical unit used for electrical energy?

In an experimental set-up as shown below,a piece of silver was placed touching points $A$ and $B$. Next time it was replaced by a piece of wood. In which case did the bulb glow? Give reason to justify the observation.

Nichrome is used to make the element of an electric heater. Why?