Magnetic effects of electric current

What is magnetic field?

• “The region surrounding a magnet, in which the force of the electrons can be detected ,

• “The region surrounding a magnet, in which the power of the magnet can be detected ,

• “The region surrounding a magnet, in which the force of the electricity can be detected ,

• “The region surrounding a magnet, in which the force of the magnet can be detected ,

which of the following is not a property of magnentic lines of force

• The lines along which the iron filings align themselves represent magnetic field lines.

• Magnetic field is quantity that has both direction and magnitude.

• The strength of the magnetic field is weaker at the pole.

• The magnetic field lines are closed curves.

Imagine that you are holding a current-carrying straight conductor in your right hand such that the

• Thumb points towards the direction of current.

• Thumb points towards the direction of magnetic lines of force

• fingers will wrap around the conductor in the direction of the field of electric current

• The magnetic field lines are closed curves.

If there is a circular coil having “n” turns, the field produced is

• “2n” times as large as that produced by a single turn.

• “n” times as large as that produced by a single turn.

• “n²” times as large as that produced by a single turn.

• “n³” times as large as that produced by a single turn.

which one is not a devices that use current-carrying conductor and magnetic fields

• Electric motor,

• electric generator,

• loudspeakers,

• electric Heater

The soft Iron core, on which the coil is wound, plus the coils , is called

• an Armature

• a coil

• a motor

• a generator

Fleming’s right -hand rule which of the following not correct

• Forefinger points in the direction of magnetic field

• Middle finger in the direction of induced current

• Middle finger in the direction of current

• The thumb will points in the direction of motion of conductor.

A device that reverses the direction of flow of current through a circuit is called a

• an Armature

• commutator

• Rings

• Brushes

which situations overloading can NOT occur in electrical circuits?

• Live wire and the neutral wire come into direct contact.

• By connecting too many appliances to a single socket. Overloading can occurs.

• By connecting heating devices in Lighting circuit .

• Suitable capacity of Conductors are used for proper electrical devices.

Red insulation covered wire represents

• live wire

• neutral wire

• earth wire

• copper wire