61- Magnetic intensity can be measured as
(A) derivative of magnetic potential
(B) negative derivative of magnetic potential
(C) square of magnetic potential
(D) integral over a cycle of-magnetic potential
62- In LED, which one of the following materials when used produces infrared radiation?
(A) Ga As
(B) Ga P
(C) Ga S
(D) Ga As P
63- The process of skin effect relates ___ and ___ .
(A) A.C. voltage and the frequency
(B) Current density and the applied AC frequency
(C) Current and AC frequency
(D) Voltage and AC frequency
64- A resonance curve for a series circuit is a plot of frequency versus
(A) voltage
(B) impedance
(C) current
(D) reactance
65- In which of the following type of material, the magnetic susceptibility does not depend on temperature
(A) diamagnetic
(B) paramagnetic
(C) ferromagnetic
(D) ferrite
66- A voltage source whose internal resistance is infinity is called
(A) constant voltage source
(B) constant resistance source
(C) variable current source
(D) constant current source
67- The unit of magnetic moment of a magnet is
(A) Ampere turns per meter
(B) Weber
(C) Weber-meter
(D) Weber meter square
68- Semi-conductors are classified based on the number of ___ and ___ .
(A) electrons and protons
(B). holes and protons
(C) holes and free electrons
(D) electrons and neutrons
69- The principle involved in Dynamo is
(A) kinetic energy to electrical energy
(B) mechanical energy to kinetic energy
(C) mechanical energy is converted to electrical energy
(D) kinetic energy to magnetic energy
70- Paramagnetic substances in a magnetic field
(A) set themselves at right angles to the field
(B) set themselves along the field
(C) oscillate about the direction of field
(D) move along the field
ANSWERS:
61-(B), 62-(A), 63-(B), 64-(C), 65-(A), 66-(D), 67-(C), 68-(C), 69-(C), 70-(B)