Basic Electrical Engineering MCQs Part 5

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:

1. Increases
2. Decreases
3. Remains constant
4. May increase or decrease

Correct answer: 3. Remains constant

A potential difference of 6 V is applied across a conductor that has resistance 3 Ω. The number of electrons flowing in 1s are

A potential difference of 6 V is applied across a conductor that has resistance 3 Ω. The number of electrons flowing in 1s are:

1. 1.07 * 10^19
2. 1.21 * 10^19
3. 1.25 * 10^19
4. 1.39 * 10^19

Correct answer: 3. 1.25 * 10^19

Explanation: Solution:

I = q/t = ne/t or n = It/e

n = 2 * 1 / (1.6*10^-19 C) = 1.25 * 10^19

The specific resistance of material that is 3 m long and has 3 m^2 area of cross and having resistance value 1.2 * 10^-8 ohms is

The specific resistance of material that is 3 m long and has 3 m^2 area of cross and having resistance value 1.2 * 10^-8 ohms is:

1. 1.2 * 10^-8 ohms
2. 1.4 * 10^-8 ohms
3. 2.38 * 10^-8 ohms
4. 4.4 * 10^-8 ohms

Correct answer: 1. 1.2 * 10^-8 ohms

A resistor R1 dissipates certain amount of power ‘P’ when it is connected to a power source. Another resistor R2 is connected in series to R1. The power dissipated by R1

A resistor R1 dissipates certain amount of power ‘P’ when it is connected to a power source. Another resistor R2 is connected in series to R1. The power dissipated by R1:

1. Increases
2. Decreases
3. Will remain the same
4. None of above

Correct answer: 2. Decreases

A resistor having color coding:

Yellow Violet Orange Silver will have resistance

Yellow Violet Orange Silver will have resistance:

1. 4.7 kΩ ± 10%
2. 47 kΩ ± 10%
3. 2.7 kΩ ± 10%
4. 27 kΩ ± 10%

Correct answer: 2. 47 kΩ ± 10%

Explanation:

Yellow, Violet = 47

Orange = 10^3

Silver = ±10% tolerance