Very Short Question and Answers - Factors Affecting Resistance

Resistance is the property of a material that opposes the flow of electric current, measured in ohms (Ω).

The formula is R = ρ × (L/A), where R is resistance, ρ is resistivity, L is length, and A is area of cross-section.

If the length is doubled, resistance also doubles.

If the area is doubled, resistance becomes half.

Different materials have different resistivities; materials with higher resistivity have greater resistance.

Resistivity is a material-specific property indicating how strongly it resists current flow, measured in ohm-meter (Ω·m).

Copper will have lower resistance because it has lower resistivity than iron.

They are made thick to increase area of cross-section, thereby reducing resistance and minimizing energy loss.

The resistance of most metals increases with temperature.

In electric heaters, high resistance wires (like nichrome) are used to generate heat.

Because a larger area allows more electrons to flow simultaneously, decreasing opposition to current or resistance.

No, resistivity is a property of the material itself and does not depend on its shape or size.

The iron wire has greater resistance because iron's resistivity is higher than that of silver.

The SI unit of resistance is ohm (Ω) and of resistivity is ohm-meter (Ω·m).

The new resistance: R' = ρ × (3L/2A) = (3/2) × original resistance, thus R' = 1.5R.

Fuses need to melt at particular current levels, so they are made from materials with precise resistivity to ensure they break the circuit at desired currents.

Increasing the thickness (area) reduces the resistance, which is important for long cords to minimize energy loss and heat buildup.

R = ρ × (2L/2A) = ρ × (L/A), so the resistance remains unchanged.

For semiconductors, resistance decreases as temperature increases.

By selecting materials with desired resistivity, engineers can control the resistance and thus the current and power distribution in circuits for specific applications.