Exercise

The strength of magnetic field produced by current carrying solenoid depends on

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?

Which effect of current is utilised in detecting a current-carrying wire concealed in a wall?
(Choose from: heating effect / magnetic effect / chemical effect)

An electron enters a magnetic field at right angles to it as shown in figure. The direction of the force acting on the electron will be:

The earth wire should be connected to the _____ (fuse/metal casing) of an appliance.

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?

What would be the most appropriate rating of the fuse you would use for a $2.0 \mathrm{kW}$ electric geyser working on a $220 \mathrm{V}$ supply?

(Choose from $5 \mathrm{A}, 8 \mathrm{A}, 9 \mathrm{A}, 10 \mathrm{A}$) 

Name the wire with which the live wire comes into contact at the event of a short-circuiting?

(Choose from the following: Neutral wire/ Live wire/ Earth wire)