Basic Electrical Engineering MCQs Part 17

Basic Electrical Engineering MCQs Part 17

An electron moves in a circle of radius 10 cm with constant speed of 6*10^6 m/s. Electric current at a point on circle is:

An electron moves in a circle of radius 10 cm with constant speed of 6*10^6 m/s. Electric current at a point on circle is:

1. 1.10 * 10^-12 A
2. 1.47 * 10^-12 A
3. 1.52 * 10^-12 A
4. 1.69 * 10^-12 A

Correct answer: 3. 1.52 * 10^-12 A

Explanation:

Solution:

Number of revolutions made by electrons in one second = v/2πr = (6*10^6)/2π*0.1 m = 9.54 * 10^6

Charge crossing the point on circle per second = Number of revolutions * 1.6 * 10^-19

Charge crossing the point on circle per second = 1.5*10^-12 A

Electric current in metallic conductors is due to flow of

Electric current in metallic conductors is duet to flow of:

1. Electrons only
2. Protons only
3. Both of above
4. Neutral atoms only

Correct answer: 1. Electrons only

The hot resistance o electric bulb filament is higher as compared to its cold filament, since the temperature coefficient of filament is

The hot resistance o electric bulb filament is higher as compared to its cold filament, since the temperature coefficient of filament is:

1. Positive
2. Zero
3. Negative
4. None of these

Correct answer: 1. Positive

In a certain circuit having constant resistance, the current is triped. The power increases

In a certain circuit having constant resistance, the current is triped. The power increases:

1. 1/3 times
2. 3 times
3. 1/9 times
4. 9 times

Correct answer: 4. 9 times

Specific resistance of a wire is dependent on

Specific resistance of a wire is dependent on:

1. Its dimensions
2. Its length
3. Its material
4. Its cross-sectional area

Correct answer: 3. Its material