Sample Problems on Electrical Resistance
Problem 1: What is the resistance of the circuit in which the applied voltage is 12 V and the current flowing through it is 4 A?
Solution:
Given,
- V = 12 V
- I = 4 A
According to the relation
R = V/I
Therefore,
R = 12 V/4 A
R = 3 Ω
Thus, the electrical resistance of the circuit is 3 Ω
Problem 2: What is the current flowing through the circuit in which the applied voltage is 12 V and the resistance of the conductor is 3 ohms?
Solution:
Given:
- V = 12 V
- R = 3 Ω
According to the relation, V = IR
⇒ I = V/R
I = 12 V/3 Ω
I = 4 A
Thus, the current flowing through the circuit is 4 A.
Problem 3: What is the voltage applied to the circuit in which the current passing through the conductor is 4 A and the resistance of the conductor is 3 Ω?
Solution:
Given:
- I = 4 A
- R = 4 Ω
According to the relation
V = IR
⇒ V = 4 A × 3 Ω
⇒ V = 12 V
Thus, the voltage across the circuit is 12 V.
Problem 4: Calculate the resistance of a copper wire of length 4 m and the area of cross-section 10-6 m2. The resistivity of copper is 1.7 × 10-8 Ωm.
Solution:
Using formula,
R = (ρ×L)/A
⇒ R = (1.7 x 10-8 Ωm) × 4 m/10-6 m2
⇒ R = 6.8×10-2 Ω
The resistance of the copper wire is 6.8×10-2 Ω
Problem 5: A copper wire of length 4 m and area of cross-section 10-6 m2 has a resistance of 6.8 × 10-2 ohms. Calculate the resistivity of copper.
Solution:
Using formula
ρ = (R×A)/L
ρ = (6.8 × 10-2) × 10-6 / 4
ρ = 1.7 × 10-8 Ωm.
Thus, the resistivity of the copper wire is 1.7 × 10-8 Ωm.
Electrical Resistance
Electrical resistance is the obstruction offered by the material in the flowing of the current or charge through the material. Thus, the higher the resistance the lower the amount of current passing through it. It is the property of a material that tells us about the flow of the current through the material. The substances that easily conducts the electric current are called conductors and they have very low electrical resistance, on the contrary, the substance that does not easily conducts the electric current are called insulators and they have very high resistance.
In this article, we will learn about, electrical resistance, its formula, factors affecting electrical resistance, and others in detail.
Table of Content
- What is Electrical Resistance?
- Resistance Formula
- Factors Affecting Resistance
- Electrical Resistor Symbol
- What is Resistivity?
- Difference Between Resistance And Resistivity