Resistance SAQ

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What is the relationship between voltage and current in determining the resistance of an object?

The resistance of an object is the ratio of voltage across it to the current through it.

What is the unit of measurement for resistance in SI Units?

Ohm (Ω)

What happens to a material as electricity flows through it?

It heats up.

What is a type of resistor whose resistance can be varied?

A variable resistor, e.g. a Rheostat Signup and view all the answers

What is the formula that describes the relationship between voltage, current, and resistance in a conductor?

V = IR Signup and view all the answers

What is the S.I. unit of power, and what is it equivalent to?

Watts (W), equivalent to Joules per second Signup and view all the answers

What is the formula that relates power to voltage and current?

P = VI Signup and view all the answers

What instrument can be used to measure the resistance of a conductor?

An ohmmeter Signup and view all the answers

Why is it advantageous to use high-voltage transmission lines for electrical power distribution?

Higher voltage transmission lines reduce the current flowing through them, resulting in less heat produced and lost, thus reducing energy waste. Signup and view all the answers

In a series circuit, what is the characteristic of the current at every point along the wire?

The current is the same at every point along the wire. Signup and view all the answers

What is the relationship between current and voltage in a transmission line, and how does it affect heat production?

As voltage increases, current decreases, resulting in less heat production and energy waste. Signup and view all the answers

How does the current change in parallel parts of a circuit, and what is the condition at the junctions?

Different size currents can flow through parallel parts of a circuit, but the size of the current at the junction entering and junction exiting the parallel parts is the same. Signup and view all the answers

What is the underlying principle that explains why high-voltage transmission lines are more efficient than low-voltage lines?

Joule's law, which states that heat produced in a conductor is proportional to the square of the current flowing through it. Signup and view all the answers

In a parallel circuit, what is the relationship between the total current and the currents in each branch?

The total current is equal to the sum of the currents in each branch. Signup and view all the answers

What is the formula for the total resistance of resistors in series?

RT = R1 + R2 +... Signup and view all the answers

How do the potential differences of the individual components in a circuit relate to the total potential difference of the circuit?

The total potential difference is equal to the sum of the potential differences of the individual components. Signup and view all the answers

What is the formula for the total resistance of resistors in parallel?

1/RT = 1/R1 + 1/R2 +... Signup and view all the answers

What is the relationship between the currents entering and leaving a point in a parallel circuit?

The sum of the currents entering a point is equal to the sum of the currents leaving it. Signup and view all the answers

What is the physical quantity that is affected by the resistivity, length, and cross-sectional area of a conductor?

Resistance Signup and view all the answers

What are wheatstone bridges used for and what is the fundamental formula about them?

Wheatstone bridges are used to find the resistance of an unknown resistor. R1/R2 = R3/R4 Signup and view all the answers

What are the factors that affect the resistance of a metallic conductor?

Resistivity, length, cross-sectional area, and temperature Signup and view all the answers

What is the SI unit of resistivity?

Ohm meter (Ωm) Signup and view all the answers

What is the relationship between the resistance of a body and its resistivity, length, and cross-sectional area?

ρ = RA/l Signup and view all the answers