Basic Electrical Engineering MCQs Part 3
Contents
- 1 A substance having number of valence electrons equal to 4 is usually
- 2 Constantan wire is used for making standard resistor since it has
- 3 The specific resistance of material of wire depends on
- 4 Electric current in liquids is due to flow of
- 5 An electron is moving in cirlce of radius 4.5*10^-11 m at a frequency of 5.28*10^15 revolutions per second. The equivalent current is approximately
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 has
Constantan wire is used for making standard resistor since it has:
- High specific resistance
- Low specific resistance
- High melting point
- Negligibly small temperature coefficient of resistance
Correct answer: 4. Negligibly small temperature coefficient of resistance
The specific resistance of material of wire depends on
The specific resistance of material of wire depends on:
- Mass
- Length
- Area of cross-section
- None of these
Correct answer: 4. None of these
Explanation: Electrical resistivity also known as specific electrical resistance or volume resistivity is a fundamental property of a material that measures how strongly it resists electric current. The specific resistance of material of wire depends on the material from which it is fabricated and it doesn’t depends on the mass, length or area of cross-section of material.
Electric current in liquids is due to flow of
Electric current in liquids is due to flow of:
- Electrons
- Positive ions
- Negative ions
- 2 and 3
Correct answer: 4. 2 and 3
An electron is moving in cirlce of radius 4.5*10^-11 m at a frequency of 5.28*10^15 revolutions per second. The equivalent current is approximately
An electron is moving in cirlce of radius 4.5*10^-11 m at a frequency of 5.28*10^15 revolutions per second. The equivalent current is approximately:
- 4.2 * 10^-4 A
- 2.3 * 10^-4 A
- 5.86 * 10^-4 A
- 8.45 * 10^-4 A
Correct answer: 4. 8.45 * 10^-4 A
Solution:
Current = Charge/Time period = Charge * Frequency
=1.6810^-19 * 5.28*10^15 = 8.45 * 10^-4 A
The drift velocity of free electrons is of the roder:
- 1 m/s
- 10^-3 m/s
- 10^-5 m/s
- 10^-9 m/s
Correct answer: 3. 10^-5 m/s