8. A variable capacitor is one whose capacitance
A. changes with change in temperature
B. changes when voltage is applied
C. can be changed by mechanical means
D. can be changed by changing the dielectric
9. The best way to remove static electricity from machinery is to
A. ground framework
B. insulate machinery
C. humidify the surrounding air
D. remove friction
10. A sphere of radii lm can attain a maximum potential of
A. 3 x 106 V.
B. 30 kV.
C. 1,000 V.
D. 3 kV.
11. During dielectric breakdown of a capacitor
A. permanent conduction path is established between capacitor plates.
B. electrons are scattered.
C. electrons cease to move from one plate to another.
D. none of the above.
12. Dielectric strength of a material depends on
C. moisture content.
D. all of these.
13. Dilelectric strength of a medium
A. increases with the increase in temperature.
B. decreases with the increase in thickness.
C. increases with moisture content.
D. is not affected by the moisture content.
14. A medium behaves like dielectric when the
A. displacement current is just equal to the conduction current.
B. displacement current is less then the conduction current.
C. displacement current is much greater than the conduction current.
D. displacement current is almost negligible.
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