Question: Both the number of turns and the core length of an inductive coil are doubled. Its self-inductance will be_____________?

• 1. unaffected
• 2. doubled
• 3. halved
• 4. quadrupled

Question: Higher the self-inductance of a coil_____________?

• 1. lesser its weber-turns
• 2. lower the e.m.f. induced
• 3. greater the flux produced by it
• 4. longer the delay in establishing steady current through it

Question: Which of the following circuit element stores energy in the electromagnetic field ?

• 1. Inductance
• 2. Condenser
• 3. Variable resistor
• 4. Resistance

Question: The current zero interruption, in oil and air blast circuit breakers, is achieved by____________?

• 1. lengthening of the gap
• 2. cooling and blast effect
• 3. both (A) and (B)
• 4. deionizing the oil with forced air

Question: The current zero interruption, in oil and air blast circuit breakers, is achieved by_______________?

• 1. lengthening of the gap
• 2. cooling and blast effect
• 3. both A and B
• 4. deionizing the oil with forced air

Question: The relay operating speed depends upon_________________?

• 1. the spring tension
• 2. the rate of flux built up
• 3. armature core air gap
• 4. all of the above

Question: Relays can be designed to respond to changes in________________?

• 1. resistance, reactance or impedance
• 2. voltage and current
• 3. light intensity
• 4. all above

Question: An efficient and a well designed protective relaying should have_____________?

• 1. good selectivity and reliability
• 2. economy and simplicity
• 3. high speed and selectivity
• 4. all of the above

Question: A differential relay measures the vector difference between_________________?

• 1. two currents
• 2. two voltages
• 3. two or more similar electrical quantities
• 4. none of the above

Question: Protective relays are devices that detect abnormal conditions in electrical circuits by measuring_____________?

• 1. current during abnormal condition
• 2. voltage during abnormal condition
• 3. constantly the electrical quantities which differ during normal and abnormal conditions
• 4. none of the above