Magnetic Effects of Electric Current Test - 11

The  mains supply is delivered to houses using a three core wiring called the live neutral and the earth . The live wire is red in colour and bring in the current, the neutral coloured blue is the return wire. The earth is green or yellow. These wire supply electricity to separate circuit within the house.

When a straight coil and a magnet are moved relative to each other, a current is induced in the coil. This phenomenon is known as electromagnetic induction.

(A) Hans Christian Oersted, a Danesh physicist first noticed the magnetic effect of electric current.
(B) The strength of a magnetic field can be observed from the degree of closeness of the field lines. Where magnetic fields are closer magnetic strength is high as near poles of a magnet, and where these are far apart magnetic strength is weak.
Statement (A) and (B) are true statement.

(A) The line joining the poles of the bar magnet to called an axis of the magnet.
(B) A generator converts mechanical energy into electrical energy, while a motor does the opposite - it converts electrical energy into mechanical energy.
Statement A is true and statement B is false.

Tangent indicates the direction of the magnetic field. It just an alternative used when compass is not available

(1) The direction of induced current in a straight conductor is given by Fleming’s right hand rule.
It states that if we stretch the thumb, forefinger and the middle finger of right hand at right angles to one another in such a way that the forefinger points in the direction of magnetic field.
Then, thumb gives the direction of motion of conductor (force), forefinger indicates direction of magnetic field and the middle finger points the direction of induced current.
(2) The direction of force which acts on the current-carrying conductor placed in a magnetic field is given by Fleming’s left hand rule. It states that if the forefinger, thumb and middle finger of left hand are stretched mutually perpendicular and the forefinger points along the direction of external magnetic field, middle finger indicates the direction of current, then thumb points along the direction of force acting on the conductor.
(3) Electromagnetic induction is the process of generating electric current with a magnetic field. It occurs whenever a magnetic field and an electric conductor, such as a coil of wire, move relative to one another.
(4) High powered electrical appliances are connected to the earth by Earthing wire.

(1) Michael Faraday is credited with the discovery of electromagnetic induction on August 29, 1831.
(2) A current-carrying conductor, when placed in a magnetic field, experiences a force. if the direction of magnetic field and that of current are mutually perpendicular then force acting on the conductor will be perpendicular to both and will be the given by Fleming’s left-hand rule.
(3) The direction of the magnetic field lines of force around a conductor is given by the Maxwell's right hand grip rule or the right handed corkscrew rule.​
(4) Hans Christian Oersted discover Electromagnetism.

(1) Green wire stands for grounding/ earthing in electric circuit.
(2) A dry cell is a type of battery. It always produces a DC current.
(3) A solenoid is a coil wound into a tightly packed helix.
(4) An electromagnet is a temporary magnet which magnetic field is produced by the flow of electric current in a coil wound round a soft iron core.

(1) Dynamo is a device that makes direct current electric power using electromagnetism. It is also known as a generator. Dynamos and generators work using the wild complex phenomena of electromagnetism.
(2) Magnetism is one aspect of the combined electromagnetic force. It refers to physical phenomena arising from the force caused by magnets, objects that produce fields that attract or repel other objects.
3) A generator converts mechanical energy into electrical energy, while a motor converts electrical energy into mechanical energy. Both the devices work because of electromagnetic induction, which is when a voltage is induced by a changing magnetic field.
(4) Andre-Marie Ampere was a French physicist and mathematician who was one of the founders of the science of classical electromagnetism. The SI unit of measurement of electric current, the ampere, is named after him.

(1) Appliances with exposed metal parts always need three pin plug i.e. positive, negative and neutral.
(2) Direct current (DC) is the unidirectional flow of electric charge. A battery is a good example of a DC power supply.
(3) The current which changes its directions periodically, such type of current is called alternating current.
(4) Electric motor is a device which makes use of the fact that magnetism in presence of electricity, produces motion.