# Conduction and breakdown in gases - Electrical Engineering (MCQ) questions and answers

1)   The Townsend mechanism explains the phenomenon of breakdown

a. Only at low pressure
b. Only at high pressure
c. Only at very high pressure
d. Only bat very low pressure
 Answer  Explanation ANSWER: Only at low pressure Explanation: No explanation is available for this question!

2)   Formative time lag depends on the mechanism of the avalanche growth in gap. The formative time lag is usually

a. Much shorter than the statistical time lag
b. Much greater than the statistical time lag
c. Equal to the statistical time lag
d. None of these
 Answer  Explanation ANSWER: Much shorter than the statistical time lag Explanation: No explanation is available for this question!

3)   Field in case of rod gaps and sphere gaps are

a. Uniform, uniform
b. Uniform, non-uniform
c. Non-uniform, uniform
d. Non-uniform, non-uniform
 Answer  Explanation ANSWER: Non-uniform, uniform Explanation: No explanation is available for this question!

4)   For the high voltage conductors at high pressures, if the voltage is positive then the corona appears as a

a. Uniform bluish white sheath
b. Reddish glowing spots
c. Uniform greenish spots
d. None of these
 Answer  Explanation ANSWER: Uniform bluish white sheath Explanation: No explanation is available for this question!

5)   According to the Paschen’s Law, the breakdown voltage of a uniform field gap is

a. Directly proportional to the gas pressure and inversely proportional to the electrode gap
b. Inversely proportional to the gas pressure and directly proportional to the electrode gap
c. Directly proportional to the both electrode gap and gas pressure
d. Inversely proportional to the both electrode gap and gas pressure
 Answer  Explanation ANSWER: Directly proportional to the both electrode gap and gas pressure Explanation: No explanation is available for this question!

6)   The statistical time lag depends upon the

a. Size of gap
b. Quantity of radiation that produces the primary electrons
c. Amount of pre-ionization preset gap
d. All of these
 Answer  Explanation ANSWER: All of these Explanation: No explanation is available for this question!

7)   A gas in normal state is almost a perfect

a. Conductor
b. Insulator
c. Semi-conductor
d. Dielectric
 Answer  Explanation ANSWER: Insulator Explanation: No explanation is available for this question!

8)   Druyesteynian distribution applies when the ion energy is much

a. Greater than the thermal energy
b. Lesser than the thermal energy
c. Equal to the thermal energy
d. None of these
 Answer  Explanation ANSWER: Greater than the thermal energy Explanation: No explanation is available for this question!

9)   Inelastic collisions are those in which internal changes in energy take place within an atom or a molecule at the expenses of total kinetic energy of the colliding particle. Suitable example for inelastic collisions is/are

a. Ionization
b. Attachment
c. Excitation
d. All of these
 Answer  Explanation ANSWER: All of these Explanation: No explanation is available for this question!

10)   Which theory explains the mechanism for breakdown under different conditions?

a. Townsend theory
b. Streamer theory
c. Clump theory
d. Only (a) and (b)
 Answer  Explanation ANSWER: Only (a) and (b) Explanation: No explanation is available for this question!