Basic Electrical Engineering MCQs Part 17

Contents

- 1 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:
- 2 Electric current in metallic conductors is due to flow of
- 3 The hot resistance o electric bulb filament is higher as compared to its cold filament, since the temperature coefficient of filament is
- 4 In a certain circuit having constant resistance, the current is triped. The power increases
- 5 Specific resistance of a wire is dependent on

## 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:

- 1.10 * 10^-12 A
- 1.47 * 10^-12 A
- 1.52 * 10^-12 A
- 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:

- Electrons only
- Protons only
- Both of above
- 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:

- Positive
- Zero
- Negative
- 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:

- 1/3 times
- 3 times
- 1/9 times
- 9 times

Correct answer: 4. 9 times

## Specific resistance of a wire is dependent on

Specific resistance of a wire is dependent on:

- Its dimensions
- Its length
- Its material
- Its cross-sectional area

Correct answer: 3. Its material