Electrostatics Online MCQ Practice Tests - Set 04 - ObjectiveBooks

# Practice Test: Question Set - 04

1. For making a capacitor, it is better to select a dielectric having
(A) Low permittivity
(B) High permittivity
(C) Permittivity same as that of air
(D) Permittivity slightly more than that of air

2. Which of the following statements is correct?
(A) Air capacitors have a black band to indicate the outside foil
(B) Electrolytic capacitor must be connected in the correct polarity
(C) Ceramic capacitors must be connected in the correct polarity
(D) Mica capacitors are available in capacitance value of 1 to 10 pF

3. The sparking between two electrical contacts can be reduced by inserting a
(A) Capacitor in parallel with contacts
(B) Capacitor in series with each contact
(C) Resistance in line
(D) None of the above

4. The capacity of capacitor bank used in power factor correction is expressed in terms of
(A) kW
(B) kVA
(C) kVAR
(D) Volts

5. Which of the following statements is incorrect?
(A) The thinner the dielectric, the more the capacitance and the lower the voltage breakdown rating for a capacitor
(B) A six dot mica capacitor color coded white, green, black, red and yellow has the capacitance value of 500 pF
(C) Capacitors in series provide less capacitance but a higher voltage breakdown rating for the combination
(D) A capacitor can store charge because it has a dielectric between two conductors

6. The potential gradient across the material of low permittivity is than across the material of high permittivity.
(A) Smaller
(B) Greater
(C) Both (A) and (B)
(D) None of the above

7. At a point is equal to the negative potential gradient at that point.
(A) Electric intensity
(B) Electric flux
(C) Magnetic flux
(D) Magnetic flux density

8. What will happen to an insulating medium if voltage more than the breakdown voltage is applied on it?
(A) It will become magnetic
(B) It will melt
(C) It will get punctured or cracked
(D) Its molecular structure will get changed

9. The ohmmeter reading for a short circuited capacitor is
(A) Infinity
(B) Few kilo ohms
(C) Few mega-ohms
(D) Zero

10. A positive and a negative charge are initially 50 mm apart. When they are moved close together so that they are now only 10 mm apart, the force between them will be
(A) 5 times smaller than before
(B) 5 times greater than before
(C) 10 times greater than before
(D) 25 times larger than before

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