Electricity Test - 6

The generation of electrical energy by a Dynamo is based on a principle of magnetism called electromagnetic induction. When the lines of force that pass from the north to the south pole of a magnet are cut by a wire, there is current induced in the wire. That is, if we take a loop or coil of wire which has no current in it and a magnet which also has no current, and move the loop or coil between the poles, loops or coils are used instead of one loop, current may be generated continuously. This method of generating electric current is called electromagnetic induction.

A transformer is an electrical device that is used to change the voltage in alternating current (AC) electrical circuits. The ability of this device to change voltage is a major advantage of AC electricity over direct current (DC).

In order to convert a galvanometer into an ammeter, a very low resistance known as "Shunt" resistance is connected in parallel to galvanometer. The value of shunt is so adjusted that most of the current passes through the shunt. In this way, a galvanometer is converted into an ammeter and can measure heavy currents without fully deflected.

According to the right hand rule, when the current is flowing upwards (north), the magnetic field will be in an anti-clockwise direction. According to this question, magnetic field will be directed towards east.

Kilowatt hour meter (kWh) is an electric meter that measures the amount of electrical energy in kWh consumed in the houses. The cost of electricity bill is calculated by multiplying the number of kWh that was consumed at the cost of 1 kWh.

In India, residential power supplied is two-wire 220 volts. Peak value is the maximum value and this is equal to √2 times the RMS value. So, the peak voltage in India is √2 × 220.

The reason of the battery failure is typically because it has built up enough internal resistance that it can no longer supply a useful amount of power to an external load. That is why, the value of internal resistance of an ideal battery or a cell is zero.

A long magnetic needle of length L, having a magnetic moment M and pole strength m units, is broken into two at the middle. The magnetic moment and pole strength of each piece will be M/2 , m respectively