Choose correct statement about magnetic lines of force
Lines of force are not imaginary lines
Can not be mapped on paper
Do not intersect each other
Always intersect each other.
Which of the following device reverses the direction of flow of current through a circuit ?
Commutator
Rheostat
Ammeter
Voltmeter
SI unit of magnetic field is
Tesla
Volt
Joule
Ampere
The regions of concentrated magnetic strength inside the magnet just near its ends are
Magnetic poles
Magnetic field
Magnetic Ends
None of these
The wire having red plastic covering is
Live wire
neutral wire
Earth wire
None
An insulated wire wound in the form of a helix with a large no of turns in
A solenoid
A toroid
A galvenoscope
Emulators
Electromagnets are used in
Electric bells
Telephone
Dynamo
All of these
The potential difference between live wire and neutral wire in India is
110 V
50 V
220 V
The wire having a green plastic covering is a
Neutral wire
The depletion layer in the PN junction region is caused by
Drift of holes
Diffusion charge carriers
Migration of impurity atoms
Drift of electrons
