Electric Current (Physics) Part-I

Electric motor is a device which converts electrical energy into mechanical energy. Electric motors involve rotating coils of wire which are driven by the magnetic force exerted by a magnetic field or an electric current.

Electric motor is a device which converts electrical energy into mechanical energy. Electric motors involve rotating coils of wire which are driven by the magnetic force exerted by a magnetic field or an electric current.

Among the above options, both Dynamo and Electric motor are such devices that work on the principle of electromagnetic induction. Dynamo converts mechanical energy into electrical energy and electric motor converts electrical energy into mechanical energy.

An electrical battery is a device consisting of two or more electrochemical cell that converts stored chemical energy into electrical energy.

There are different types of batteries but all have three basic components; a positive electrode, negative electrode, and electrolyte.

Electric motors operating at low voltages tend to burn out because they draw more current which is inversely proportional to the voltage.

The Faraday constant represents the magnitude of electric charge per mole of electrons. It is denoted by the symbol 'F' and is named after English scientist Michael Faraday. It is a universal constant. It has the currently accepted value F-96485.332123 C.mol⁻¹.

A motor car battery usually has six 2V cells connected in series, which gives it a steady voltage of about 12V. The capacity of battery is expressed in ampere-hour.

An ampere-hour is the total amount of electrical charge transferred when a current of one ampere flows for one hour. Therefore the total usable charge stored in a battery can be stated in term of ampere-hour.

The electrolyte used is a approx. 35% solution by weight of sulphuric acid H₂SO₄ with 65% of water. The electrodes used in motor car batteries are lead (Pb) and lead dioxide (PbO₂).

The nickel-cadmium battery is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes, while potassium hydroxide is used as alkaline electrolyte.

It is used in calculator, cordless electronic appliances, transistors, portable power tools, photography equipments, flashlight etc.

Tungsten metal is used as filament in lighting bulbs. In 1781, Carl Wilhelm Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing tungsten acid.

Two years later in 1783, Juan Jose and Fausto Elhuyar were the first to isolate tungsten through the reduction of this acid with charcoal.

For this reason, they are credited with the discovery of this element. It's melting point is 3422°C and it's boiling point is 5555°C.

Tungsten metal is used as filament in lighting bulbs. In 1781, Carl Wilhelm Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing tungsten acid.

Two years later in 1783, Juan Jose and Fausto Elhuyar were the first to isolate tungsten through the reduction of this acid with charcoal.

For this reason, they are credited with the discovery of this element. It's melting point is 3422°C and it's boiling point is 5555°C.