Basic Electrical Engineering MCQs Part 5 As temperature of metallic resistor is increased, the product of its resistivity and conductivity As temperature of metallic resistor is increased, the product of its resistivity and conductivity: Increases Decreases Remains constant May increase or decrease Correct answer: 3. Remains constant A potential difference of 6 V is applied … Read more
Transformer MCQs Part 16 At full-load certain transformer has 400 W iron loss. The iron loss at half-full load will have value At full-load certain transformer has 400 W iron loss. The iron loss at half-full load will have value: 50 W 100 W 200 W 400 W Correct answer: 4. 400 W Explanation: Iron … Read more
Basic Electrical Engineering MCQs Part 4 If a piece of wire is melted and recast to half of its original length, the new resistance is If a piece of wire is melted and recast to half of its original length, the new resistance is: R R/2 R/4 2R Correct answer: 3. R/4 Explanation: Suppose R … Read more
Basic Electrical Engineering MCQs Part 3 A substance having number of valence electrons equal to 4 is usually A substance having number of valence electrons equal to 4 is usually An insulator A semiconductor A conductor None of the above Correct answer: 2. A semiconductor Constantan wire is used for making standard resistor since it … Read more
Transformer MCQs Part 15 If Zs and Zp are secondary and primary load impedances of a step-up transformer, then which of following is correct If Zs and Zp are secondary and primary load impedances of a step-up transformer, then which of following is correct: Zp < Zs Zp > Zs Zp = Zs Insufficient data … Read more
Switchgear and Protection MCQs Part 6 During short circuit test on circuit breaker following readings were obtained as single frequency transient During short circuit test on circuit breaker following readings were obtained as single frequency transient: Time to reach peak restriking voltage = 60 µsec Peak restriking voltage = 120 kV The average RRRV is … Read more
Switchgear and Protection MCQs Part 5 Which of the following device detects fault in power system Which of the following device detects fault in power system Relay Circuit breaker Isolator None of these Correct answer: 1. Relay A circuit breaker is rated as 1800 A, 1000 MVA, 33 kV, 3 second, 3 phase oil circuit … Read more
Switchgear and Protection MCQs Part 4 A fuse performs A fuse performs Detection function only Interruption function only Both of these None of these Correct answer: 3. Both of these When oil circuit breaker operates under fault conditions, 1 cm³ of oil forms about When oil circuit breaker operates under fault conditions, 1 cm³ of … Read more
Transformer MCQs Part 14 Calculating transformer secondary turns numerical The no-load ratio of a 50 Hz single phase transformer is 6000/220 V. The value of maximum flux in core is 0.06 Wb. What is the number of secondary turns? 10 12 17 26 Correct answer: 17 From formula: Es = 4.44 * f * Ns … Read more
Transformer MCQs Part 13 The all-day efficiency of a lighting transformer is always _________ its power efficiency The all-day efficiency of a lighting transformer is always _________ its power efficiency: Less than Equal to Higher than None of these Correct answer: 1. Less than A 3000/150 V, 30 kVA transformer has 50 turns in secondary. … Read more