Electricity and Magnetism Test - 4

Total charge flown (Q) = number of electrons(n) × charge on the one electron (e)
Q = ne
Q = 18.75 × 10¹⁹ × 1.6 × 10^-19
Q = 30 C

The main switch, live wire, and the neutral wire are in connection to the line wires in our homes; these wires then supply electricity to separate electric circuits within the house. When the main switch of a domestic circuit is put off, it disconnects both the live and neutral wires.

A fuse protects a circuit from excess current. It will melt if the current exceeds 8 A.

All appliances need a common potential difference, so they are connected in parallel.

A fuse in an electric circuit is used to break the circuit when excessive current flows. The fuse breaks the circuit if a fault in an appliance causes too much current to flow. This protects the wiring and the appliance if something goes wrong. The fuse contains a piece of wire that melts easily. If the current going through the fuse is too great, the wire heats up until it melts and breaks the circuit.

The fact that magnetic field is associated with current was discovered by Oersted.

The fuse wire should be made of the material which should have very low melting point. Generally, it is made up of an alloy of copper and tin.

E.m.f. of a cell is the potential difference across the terminal of the cell when no current flows through the circuit. So, the units of the e.m.f. are the same as those of the potential difference, or we can say that the unit of e.m.f. of a cell is volt.