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

Question: In a circuit breaker the basic problem is to________________?

• 1. maintain the arc
• 2. extinguish the arc
• 3. transmit large power
• 4. emit the ionizing electrons

Question: The voltage appearing across the contacts after opening of the circuit breaker is called__________voltage.

• 1. recovery
• 2. surge
• 3. operating
• 4. arc

Question: Large internal faults are protected by_______________?

• 1. merz price percentage differential protection
• 2. mho and ohm relays
• 3. horn gaps and temperature relays
• 4. earth fault and positive sequence relays

Question: Directional relays are based on flow of____________?

• 1. power
• 2. current
• 3. voltage wave
• 4. all of the above

Question: Air blast circuit breaker is used for_____________?

• 1. over currents
• 2. short duty
• 3. intermittant duty
• 4. repeated duty