Basic Electrical Engineering MCQs Part 28

Contents

- 1 In gases the flow of current is due to:
- 2 The temperature coefficient of resistance of certain wire is 0.00150 per °C. At 300 K, its resistance is 1 Ω. The resistance of wire will be 2 Ω at what temp value
- 3 The total charge entering terminal of an element is given by equation
- 4 No current flows between two charged bodies when they have same
- 5 The rating of the fuse wire is always expressed in

## In gases the flow of current is due to:

In gases the flow of current is due to:

- Positive ions only
- Electrons only
- Electrons and positive ions
- Electrons, positive ions and negative ions

Correct answer: 4. Electrons, positive ions and negative ions

## The temperature coefficient of resistance of certain wire is 0.00150 per °C. At 300 K, its resistance is 1 Ω. The resistance of wire will be 2 Ω at what temp value

The temperature coefficient of resistance of certain wire is 0.00150 per °C. At 300 K, its resistance is 1 Ω. The resistance of wire will be 2 Ω at what temp value:

- 585.53 K
- 966.66 K
- 1052.33 K
- 2200 K

Correct answer: 2. 966.66 K

Explanation:

The resistance of wire at 300 K or 27° C is 1 Ω. (Since Celsius = Kelvin – 273.15)

Let’s assume R_{1} = 1 Ω

Let’s assume at t° C the resistance of wire is 2 Ω

From formula:

R_{2 }= R_{1} [ 1 + α (t – 27) ]

Where α = Temperature coefficient of resistance

OR

2 = 1 [ 1 + 0.0015 (t – 27)]

Solving above:

t = 693.66° C

Temp in Kelvin

t = 693.66 + 273 = 966.66 K

## The total charge entering terminal of an element is given by equation

The total charge entering terminal of an element is given by equation:

q = (9t^{2} – 15t)mC

The current at t = 3s is:

- 3 mA
- 6 mA
- 12 mA
- 18 mA

Correct answer: 3. 12 mA

Explanation:

i = dq/dt = d/dt (q) = d/dt (9t^{2} – 15t) mA = (9t – 15) mA

At t = 3s

i = 9(3) – 15 = 12 mA

## No current flows between two charged bodies when they have same

No current flows between two charged bodies when they have same

- Charge
- Capacity
- Potential
- None of the above

Correct answer: 3. Potential

## The rating of the fuse wire is always expressed in

The rating of the fuse wire is always expressed in:

- Ampere
- Ampere-hours
- Volts
- kWH

Correct answer: 1. Ampere

Read more: Electrical Engineering MCQs here

Also study:

- Basic Electrical Laws and Theorems
- Basic Voltage and Current MCQs
- High Voltage Engineering MCQs
- Induction Motor MCQs
- Power Electronics
- Power Distribution MCQs
- Power Generation MCQs
- Power System Protection MCQs
- Synchronous Generator MCQs
- Synchronous motor MCQs
- Transformer MCQs