Electricity

Question 1

What are the units of measurement used in electricity?

Answer 1

• ampere (A)
• coulomb (C)
• joule (J)
• ohm (Ω)
• second (s)
• volt (V)
• watt (W)

These units are essential for understanding electrical concepts and calculations.

Question 2

What is the purpose of insulation in electrical devices?

Answer 2

To protect the device or user from electric shock or short circuits

Insulation prevents accidental contact with live wires.

Question 3

What is the relationship between power, current, and voltage?

Answer 3

Power = Current x Voltage
P = I x V

This relationship helps in selecting appropriate fuses for electrical devices.

Question 4

What is the formula for energy transferred in a circuit?

Answer 4

Energy transferred = Current x Voltage x Time
E = I x V x t

This formula is crucial for calculating energy consumption.

Question 5

What are the two types of current supplied by electricity?

Answer 5

• Alternating Current (a.c.)
• Direct Current (d.c.)

a.c. is commonly used in mains electricity, while d.c. is supplied by batteries.

Question 6

In what scenarios would a series circuit be more appropriate?

Answer 6

For applications requiring the same current through all components, such as in domestic lighting

Series circuits ensure that all components share the same current.

Question 7

How does changing resistance affect current in a circuit?

Answer 7

Increasing resistance decreases the current, while decreasing resistance increases the current

This relationship is governed by Ohm’s Law.

Question 8

What is the relationship between voltage, current, and resistance?

Answer 8

Voltage = Current x Resistance
V = I x R

This formula is fundamental in circuit analysis.

Question 9

What does it mean that current is conserved at a junction in a circuit?

Answer 9

The total current entering a junction equals the total current leaving the junction

This is known as Kirchhoff’s Current Law.

Question 10

What is the significance of the voltage across components connected in parallel?

Answer 10

The voltage across two components connected in parallel is the same

This characteristic allows different components to operate independently.

Question 11

What is the definition of electric current?

Answer 11

The rate of flow of electric charge

Current is measured in amperes (A).

Question 12

What is the formula for charge in relation to current and time?

Answer 12

Charge = Current x Time
Q = I x t

This relationship helps in understanding how much charge flows over a period.

Question 13

What are electrical conductors and insulators?

Answer 13

Conductors allow electric charge to flow easily, while insulators do not

Examples of conductors include metals, while rubber is a common insulator.

Question 14

How can insulating materials be charged?

Answer 14

By friction

This process transfers electrons, creating static electricity.

Question 15

What is the nature of the force between unlike electrostatic charges?

Answer 15

There is a force of attraction between unlike charges

Conversely, like charges repel each other.

Question 16

What are some uses of electrostatic charges?

Answer 16

• Photocopiers
• Inkjet printers

These devices utilize electrostatic principles to function effectively.