Physics Rev

Question 1

What is electromagnetism?

Answer 1

Electromagnetism is a branch of physics that deals with the interaction between electric charges and magnetic fields.

Question 2

True or False: Electromagnetic forces are one of the four fundamental forces of nature.

Answer 2

True

Question 3

Fill in the blank: The unit of electric current is ______.

Answer 3

Ampere

Question 4

What is the relationship between electricity and magnetism?

Answer 4

Electricity can create magnetic fields, and changing magnetic fields can induce electric currents.

Question 5

What is a magnetic field?

Answer 5

A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials.

Question 6

What is the formula for calculating electric power?

Answer 6

Power (P) = Voltage (V) × Current (I)

Question 7

What are energy stores?

Answer 7

Energy stores are systems or materials that can hold energy for later use, such as batteries, capacitors, and fuel.

Question 8

True or False: A capacitor stores energy in the form of an electric field.

Answer 8

True

Question 9

What type of energy is stored in a battery?

Answer 9

Chemical energy

Question 10

Define electromagnetic induction.

Answer 10

Electromagnetic induction is the process by which a changing magnetic field induces an electric current in a conductor.

Question 11

What is the SI unit of magnetic flux?

Answer 11

Weber

Question 12

Fill in the blank: The principle of conservation of energy states that energy cannot be created or ______.

Answer 12

destroyed

Question 13

What is the difference between renewable and non-renewable energy sources?

Answer 13

Renewable energy sources can be replenished naturally, while non-renewable energy sources are finite and will deplete over time.

Question 14

What is Faraday’s Law of Induction?

Answer 14

Faraday’s Law states that the induced electromotive force in any closed circuit is equal to the rate of change of the magnetic flux through the circuit.

Question 15

What is the role of transformers in energy transfer?

Answer 15

Transformers change the voltage level in alternating current (AC) electrical systems to improve the efficiency of energy transfer.

Question 16

True or False: Energy can be transferred from one form to another.

Answer 16

True

Question 17

What is the formula for calculating energy stored in a capacitor?

Answer 17

Energy (E) = 1/2 × Capacitance (C) × Voltage² (V²)

Question 18

What is electromagnetic radiation?

Answer 18

Electromagnetic radiation is energy that travels through space as waves, which include visible light, radio waves, and X-rays.

Question 19

What does the term ‘electromotive force’ (EMF) refer to?

Answer 19

Electromotive force refers to the voltage generated by a source such as a battery or generator.

Question 20

Fill in the blank: The maximum energy transfer occurs when the load is ______.

Answer 20

matched

Question 21

What is the effect of resistance on energy transfer in electrical circuits?

Answer 21

Resistance reduces the amount of energy that can be transferred, leading to energy loss as heat.

Question 22

What is a superconductor?

Answer 22

A superconductor is a material that can conduct electricity without resistance when cooled below a certain temperature.

Question 23

Which law states that electric current is directly proportional to voltage and inversely proportional to resistance?

Answer 23

Ohm’s Law

Question 24

What is the primary function of an inductor in electrical circuits?

Answer 24

An inductor stores energy in a magnetic field when electric current flows through it.

Question 25

Fill in the blank: The energy stored in a magnetic field is given by the formula ______.

Answer 25

E = 1/2 L I²

Question 26

What is the difference between direct current (DC) and alternating current (AC)?

Answer 26

DC flows in one direction, while AC changes direction periodically.

Question 27

What is the purpose of a circuit breaker?

Answer 27

A circuit breaker is used to protect electrical circuits from overload or short circuits by interrupting the flow of current.

Question 28

True or False: Electromagnetic waves do not require a medium to travel.

Answer 28

True

Question 29

What are the components of an electric circuit?

Answer 29

The components include a power source, conductors, load, and sometimes switches or circuit protection devices.

Question 30

What does the term 'electric field' describe?

Answer 30

An electric field describes the force per unit charge experienced by a charged particle in the vicinity of other electric charges.

Question 31

What is the primary purpose of energy transfer systems?

Answer 31

Energy transfer systems are designed to move energy from one location or form to another efficiently.

Question 32

Fill in the blank: The principle of ______ states that the total energy in a closed system remains constant.

Answer 32

conservation of energy

Question 33

What is the role of electric generators?

Answer 33

Electric generators convert mechanical energy into electrical energy.

Question 34

What is a photovoltaic cell?

Answer 34

A photovoltaic cell is a device that converts sunlight directly into electricity through the photovoltaic effect.

Question 35

What is the significance of the Lorentz force?

Answer 35

The Lorentz force describes the force experienced by a charged particle moving through an electric and magnetic field.