Electric Circuits

Question 1

Potential difference

Answer 1

Across the ends of a conductor is the energy transferred per unit electric charge flowing through it

Question 2

Si unit of potential difference

Answer 2

Volts (v)

Question 3

Emf

Answer 3

The work done per unit charge by the source. It Is equal to the potential difference measured across the terminals of a battery when no charges are flowing in the circuit

Question 4

Terminal potential difference

Answer 4

The voltage measured across the terminals of a battery when charges are flowing in the circuit

Question 5

Current strength

Answer 5

The rate of flow of charge

Measured in Ampere(A)

Same as coulomb per second

Question 6

Why does a battery go flat

Answer 6

When all of the stored chemical energy in the battery has been converted to electrical energy

The electrical energy is converted into other forms : heat, light, kinetic, chemical

Question 7

Resistance

Answer 7

The ratio of the potential difference across a resistor to the current in the resistor

Question 8

Unit of resistance

Answer 8

One ohm is equal to one volt per ampere

Question 9

State and explain factors that effect resistance of a given material

Answer 9

Several factors influence resistance:

1. Temperature: When temperature rises, resistance usually increases because atoms vibrate more, causing more collisions with electrons.
2. Length: Longer conductors have higher resistance because electrons encounter more atoms to collide with as they travel through the material.
3. Thickness: Thicker conductors have lower resistance as they provide more pathways for electrons to move through, reducing collisions.

Question 10

Microscopic description of resistance

Answer 10

Resistance in a conductor happens because moving electrons collide with atoms, causing the atoms to vibrate and generate heat. These collisions slow down the electrons, making it harder for them to move through the conductor, thus creating resistance.

Question 11

Series circuits

Answer 11

Potential difference dividers because the total potential difference is equal to the sum of the potential differences across all the individual components

Question 12

Parallel circuits

Answer 12

Current dividers because the total current in the circuit is equal to the sum of the branch currents