Abhishek Chandra Solutions for Chapter: Magnetic Effects of Electric Current, Exercise 2: EXERCISE

A current that always flows through an electric device in the same direction is called  direct current or $\mathrm{DC}$. The polarity (positive and negative) of a direct current is fixed.

A current that reverses direction at equal intervals of time is called the alternating current or $\mathrm{AC}$. The polarity (positive and negative) of an alternating current is not fixed.

Both $\mathrm{DC}$ and $\mathrm{AC}$ can be used for lighting and heating. Some electric devices like the television need $\mathrm{DC}$ to operate. In such cases, an adapter or a device is fitted into them to convert $\mathrm{AC}$ from the mains supply to $\mathrm{DC}$.

On the basis of above information, answer the following:

For long distance transmission of electricity, which one is generally preferred?

Match the items in Column I to those in Column II.

Note: Option (c) changed from potential difference between neutral and earth wires in a domestic circuit in volts to works on heating effect of current.

Can you point out a difference in the magnetic fields of a current-carrying solenoid and coil?

What do you expect to happen if you fit an electric fuse of rating $15 \mathrm{A}$ in a circuit having a hair dryer that draws a current of $2 \mathrm{A}$ from the mains supply?

What will happen if an electric fuse is fitted into the neutral wire instead of the live wire? What will happen if it is fitted into the earth wire?

Four electric appliances are connected to the mains supply fitted with a fuse of $10 \mathrm{A}$. The ratings of the appliances are $40 \mathrm{W}, 220 \mathrm{V}; 600 \mathrm{W}, 220 \mathrm{V}; 900 \mathrm{W}, 220 \mathrm{V}; 2000 \mathrm{W}, 220 \mathrm{V}$. When all the appliances are working simultaneously, what do you expect to happen and why? To prevent the blowing up of fuse, what combinations of appliances can you use?

It is safe for birds to sit on naked power lines on top of electric poles. Explain.

What are the differences in the wiring of an electric lamp and an electric heater? Support your answer with reasons.