Carbon brushes are used in
Electric motor
Electromagnet
Bar magnet
None
Which of the following device reverses the direction of flow of current through a circuit ?
Commutator
Rheostat
Ammeter
Voltmeter
The system where due to action of an electromagnet, a circuit is activated to control a second circuit is
Electromagnetic relay
Remote control
Radar
Electric bell
An insulated wire wound in the form of a helix with a large no of turns in
A solenoid
A toroid
A galvenoscope
Emulators
The region around a magnet within which it can experience a magnetic force is called
Magnetic field
Magnetic pole
Magnet induction
Magnetic attraction
The depletion layer in the PN junction region is caused by
Drift of holes
Diffusion charge carriers
Migration of impurity atoms
Drift of electrons
The wire having a green plastic covering is a
Live wire
Neutral wire
Earth wire
Electromagnets are used in
Electric bells
Telephone
Dynamo
All of these
Commonly used safety fuse wire in made of
Copper
Pb
Ni
An alloy of tin & lead
The potential difference between live wire and neutral wire in India is
110 V
50 V
220 V
