Electric current – part (2)

Alternative current (AC) is electric current that periodically reverses direction and changes its magnitude continuously with time,in contrast to direct current (DC), which flows only in one direction. An AC current is produced by a dynamo which called AC dynamo or alternator. This is done by rotating a coil or armature within the magnetic filed created by field coils. If a DC current is required it can be supplied by a commutator in a DC dynamo. It is important to note that the current produced by a simple dynamo is alternative current (AC), as the direction of the current changes with each half turn of the coil. However, generally dynamos incorporate a component called a commutator, which convert the AC into direct current (DC).

THe rotating armature of an AC generator is connected to an external circuit by the means of slip rings. In a DC generator, the commutator is used to reverse the direction  of the  natural altenating voltage every half cycle. So AC generator has slip rings while DC generator has a commutator.

Direct current is used to charging the batteries with the help of rectifier which converts AC to DC. Thus alternate current is not preferable for it.

The Earth's magnetic field is believed to be generated by electric current in the conductive material of its core, created by convection current due to heat escaping from the core.

In artificial satellite solar(or photovoltaic) cells convert the sun's energy into electrical energy through photovoltaic effect. The photovoltaic effect is the creation of voltage and electric current in a material upon exposure to light.

The conversion of light(solar) energy into electrical energy is based on the phenomenon called photovoltaic effect. A photovoltaic cell is the basic unit of the system where the photovoltaic effect is utilized to produce electricity from light energy. Silicon is most widely used semiconductor material for constructing photovoltaic cell.

The conversion of light(solar) energy into electrical energy is based on the phenomenon called photovoltaic effect. A photovoltaic cell is the basic unit of the system where the photovoltaic effect is utilized to produce electricity from light energy. Silicon is most widely used semiconductor material for constructing photovoltaic cell.

The conversion of light(solar) energy into electrical energy is based on the phenomenon called photovoltaic effect. A photovoltaic cell is the basic unit of the system where the photovoltaic effect is utilized to produce electricity from light energy. Silicon is most widely used semiconductor material for constructing photovoltaic cell.

As on 31 March, 2024, the total wind power installed capacity of India is about 45.89 GW. Hence,statement of option (b) is not true. On the basis of  wind power installed capacity, India ranks fourth in the world after China, USA and Germany. Among Indian States, Maximum wind power potential (at 100m  above ground level) is in Gujarat.

Electric potential is a scalar quantity. It is the amount of work needed to move a unit charge from a reference point to a specific point against an electric field.