Basic Electrical Engineering MCQ Part 2

## Point Source Example

The figure below displays an electric circuit drawn using point source:

The voltmeter connected across 15 kohm resistor will read:

- 3 V
- 5 V
- 10 V
- 15 V

Correct answer: 4. 15 V

Explanation:

The circuit redrawn to normal circuit as follows:

Total input: Vin = 25 V

Using voltage divider rule:

V (15k) = (15 kohm)/(10 kohm + 15 kohm) * 25 V = 15 V

## Resistance calculation for 5 ohms wire whose length is increased four times and area by two times

A certain length of wire has resistance 5 ohms. What is the resistance of wire that is made of the same material and is four times longer and has twice the cross-sectional area:

- 2.5 ohms
- 5 ohms
- 7.5 ohms
- 10 ohms

Correct answer: 2 ohms

Explanation: Suppose R_{1} and R_{2} are values of resistances and R_{1} = 5 ohms.

From Formula *R _{1} = ρ*l_{1}/a_{1} and R_{2} = ρ*l_{2}/a_{2}*

R_{2}/R_{1} = (l_{2}/l_{1}) * (a_{1}/a_{2})

R_{2}/R_{1} = (4.l/l) * (a/2a) = (4.~~l~~/~~l~~) * (~~a~~/2~~a~~) = 4/2 = 2

*R _{2} = 2.R_{1} = 2. 5 ohms = 10 ohms*

## For constant resistor by increasing the voltage the current will

For constant resistor, by increasing the voltage, the current will:

- Increase
- Decrease
- Remain the same

Correct answer: 1. Increase

## 3 mA current flowing through 1 kohm resistance will produce a voltage drop of

3 mA current flowing through 1 kohm resistance will produce a voltage drop of:

- 0.33 V
- 1 V
- 3 V
- 3 mV

Correct answer: 3. 3 V

## Norton theorem is ___________ Thevenin theorem

Norton’s theorem is ___________ Thevenin’s theorem:

- Identical to
- Converse of

Correct answer: 2. Converse of

Explanation:

Statement of Norton’s theorem: *A linear bilateral network can be reduced to a simplified two-terminal circuit consisting of a single current source and a single shunt resistor*

Statement of Thevenin Theorem:* A linear bilateral network can be reduced to a simplified two-terminal circuit consisting of a single voltage source and a single series resistor*