?A permanent magnet repels
1). ferromagnetic substances only?
2). diamagnetic substances only
3). paramagnetic susstances only
4). both paramagnetic and diamagnetic substances
What is the difference between a ?CFL and an LED LAMP?
(1) Toproduce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semi- conductor material.
(2) The average life span of a CFL is much longer than of and LED lamp.
(3) A CFL is LESS energy -efficient as compared to an LED lamp.
Which of the statements given above is/are correct?
1). 1 only
2). 2 and 3
3). 1 and 3
4). 1, 2 and 3?
?The phenomenon of electromagnetic induction implies a production of induced
1). resistance in a coil when the magnetic field changes with time
2). current in a coil when an electric field?changes with time
3). current in a coil when a magnetic field?changes with time
4). ?voltage in a coil when a magnetic field?changes with time
Alternating current can be measured by
1). Moving coil galvanomenter?
2). Hot wire ammeter?
3). ?Tangent galvanometer?
4). None of these
A carbon microphone is best used in
1). Dynamo?
2). telephone?
3). Transformer
4). None of these?