Basic Electrical Engineering MCQs Part 7

Contents

- 1 A substance having number of valence electrons less than 4 is usually
- 2 Conductivity is reciprocal of
- 3 The specific resistance of certain wire that is 1.5 m long, has 0.5 mm diamter, and having a resistance 5 will be
- 4 The electric power dissipated in a resistor in terms of its conductance G and voltage V across it is mathematically expressed in the form
- 5 The SI unit of conductivity is

## A substance having number of valence electrons less than 4 is usually

A substance having number of valence electrons less than 4 is usually

- An insulator
- A semiconductor
- A conductor
- None of the above

Correct answer: 3. A conductor

## Conductivity is reciprocal of

Conductivity is reciprocal of:

- Resistance
- Current density
- Resistivity
- None of these

Correct answer: 3. Resistivity

## The specific resistance of certain wire that is 1.5 m long, has 0.5 mm diamter, and having a resistance 5 will be

The specific resistance of certain wire that is 1.5 m long, has 0.5 mm diamter, and having a resistance 5 will be:

- 65 * 10^-8 Ω-m
- 23 * 10^-8 Ω-m
- 37 * 10^-8 Ω-m
- 44 * 10^-8 Ω-m

Correct answer: 1. 65 * 10^-8 Ω-m

Solution:

Area = πr² = π(d/2)² = 1.963E-07

R = ρl/A OR ρ = RA/l

ρ = 5 * 1.963E-07 / 1.5 = 6.54 * 10^-07 Ω-m = 65 * 10^-8 Ω-m

## The electric power dissipated in a resistor in terms of its conductance G and voltage V across it is mathematically expressed in the form

The electric power dissipated in a resistor in terms of its conductance G and voltage V across it is mathematically expressed in the form:

- V²G
- V²/G
- GV²
- G/V²

Correct answer: 1. V²G

Explanation:

Power dissipated (P) = V²/R = V²G

## The SI unit of conductivity is

The SI unit of conductivity is:

- mho/m
- mho-m
- ohm-m
- ohm/m

Correct answer: 1. mho/m