Basic Electrical Engineering MCQs Part 14
Contents
- 1 If potential difference across conductor of material having resistivity ρ remains constant, then heat produced is proportional to:
- 2 A constant voltage is applied between two ends of uniform metallic wire. Some heat is developed. If both length and radius of wire are halved, heat developed in same duration is
- 3 The fuse wire is made of
- 4 Certain motor draws 20 A from 230 V source. If motor is 90 efficient, the horsepower rating is
- 5 Which of following is immaterial for a fuse
If potential difference across conductor of material having resistivity ρ remains constant, then heat produced is proportional to:
If potential difference across conductor of material having resistivity ρ remains constant, then heat produced is proportional to:
- 1/ρ
- Ρ
- ρ²
- 1/√ρ
Correct answer: 1. 1/ρ
A constant voltage is applied between two ends of uniform metallic wire. Some heat is developed. If both length and radius of wire are halved, heat developed in same duration is
A constant voltage is applied between two ends of uniform metallic wire. Some heat is developed. If both length and radius of wire are halved, heat developed in same duration is:
- Twice
- Same
- Half
- One-fourth
Correct answer: 3. Half
The fuse wire is made of
The fuse wire is made of:
- Copper
- Lead-tin alloy
- Tungsten
- Nichrome
Correct answer: 2. Lead-tin alloy
Certain motor draws 20 A from 230 V source. If motor is 90 efficient, the horsepower rating is
Certain motor draws 20 A from 230 V source. If motor is 90 efficient, the horsepower rating is:
- 3 HP
- 6 HP
- 12 HP
- 20 HP
Correct answer: 2. 6 HP
Solution:
Motor input = VI = 230 * 20 = 4600 W
————
Motor output = η * Motor input = 0.9 * 4600 = 4140 W
———— Horsepower rating of motor = 4140/746 = 6 HP
Which of following is immaterial for a fuse
Which of following is immaterial for a fuse:
- Length
- Radius
- Resistivity
- None of these
Correct answer: 1. Length