Technical MCQs

1. Which type of device is a circuit breaker? (A) Current interrupting device (B) Waveform correcting device (C) A device to neutralize the effects of transients (D) Power factor correction device 2. In a circuit breaker the function of a protective relay is: (A) To limit arcing current (B) To provide additional safety (C) To close contact during the operation of circuit breaker (D) To catch any stray voltage 3. Rated voltage of low voltage circuit breaker is less than: (A) 400 V (B) 500 V (C) 600 V (D) 1000 V 4. Which is the property of SF6 gas? (A) is highly toxic (B) is non-inflammable (C) Has pungent odor (D) is yellow in color 5. SF6 gas is basically the abbreviation of: (A) Sulphur difluoride (B) Sulphur hexafluoride (C) Sulphur fluoride (D) Sulphur Hexafluorine Read More : Electrical Engineering MCQs 6. The property of SF6 gas is: (A) is lighter than air (B) Has density 5 times as compared to that of air (C) Has density 2 times as compared to that of air (D) is lighter than hydr

1. Which conductor has the highest electrical conductivity? (A) Lead (B) Aluminum (C) Steel (D) Silver 2. Resistivity is expressed in terms of: (A) Micro ohm-cm (B) Ampere (C) Voltage (D) Volt meter 3. Copper has resistivity: (A) 2.56 micro ohm-cm (B) 3.52 micro ohm-cm (C) 5.54 micro ohm-cm (D) 1.56 micro ohm-cm 4. At absolute zero, copper has resistivity: (A) 2.56 micro ohm-cm (B) Negligibly small (C) 3.55 micro ohm-cm (D) 4.5 micro ohm-cm 5. If the size of copper conductor is one square millimetre, it can safely carry current of: (A) 20 A (B) 30 A (C) 10 A (D)  40 A Read More : Transformers MCQs 6. To carry 75 A current, an aluminum conductor should have minimum cross section of: (A) 15 mm 2 (B)25 mm 2 (C) 35 mm 2 (D) 45 mm 2 7. In which for copper has best conductivity: (A) Hard drawn copper (B) Pure annealed copper (C) Copper containing traces of silicon (D) Induction hardened copper 8. In which form copper has the best mechanical strength: (A) Hard drawn copper (B) Pure annealed c