ELECTRIC FIELDS

Question 1

What type of fields can electric fields be?

Answer 1

Attractive or repulsive

Question 2

What is the unit of electric charge?

Answer 2

Coulombs (C)

Question 3

What happens to oppositely charged particles?

Answer 3

They attract each other

Question 4

What happens to like charges?

Answer 4

They repel each other

Question 5

What does a charged object experience when placed in an electric field?

Answer 5

A force

Question 6

What can electric fields be represented by?

Answer 6

Field lines

Question 7

What law is used to calculate the force between two point charges?

Answer 7

Coulomb’s law

Question 8

What is the permittivity of free space denoted as?

Answer 8

ε (epsilon-nought)

Question 9

In Coulomb’s law, what does F represent?

Answer 9

The force of attraction or repulsion

Question 10

What does F become if the charges are opposite?

Answer 10

Negative

Question 11

What does F become if Q and q are like charges?

Answer 11

Positive

Question 12

What is the relationship between the force on Q and the force on q?

Answer 12

They are equal and opposite

Question 13

What type of law is Coulomb’s law?

Answer 13

Inverse square law

Question 14

What does the size of the force F depend on?

Answer 14

The permittivity of the material between the charges

Question 15

What is the permittivity of free space?

Answer 15

8.85 x 10^-12 C^2N^-1m^-2

Question 16

What is electric field strength defined as?

Answer 16

Force per unit positive charge

Question 17

What is the formula for electric field strength E?

Answer 17

E = F/Q

Question 18

What are the units of electric field strength E?

Answer 18

Newtons per coulomb (NC^-1)

Question 19

What does E represent in a radial field?

Answer 19

Electric field strength

Question 20

In a radial field, how does E depend on the distance r?

Answer 20

E is inversely proportional to r

Question 21

What direction do field lines point for a positive charge Q?

Answer 21

Away from Q

Question 22

What direction do field lines point for a negative charge Q?

Answer 22

Towards Q

Question 23

What does the area under the graph of electric field lines represent?

Answer 23

Electric potential

Question 24

What is the equation for electric field strength E between two parallel plates?

Answer 24

E = V/d

V is the potential difference between the plates, and d is the distance between them.

Question 25

How is electric field strength E measured?

Answer 25

In volts per metre (Vm^-1) ## Footnote This measurement indicates the strength of the electric field.

Question 26

What does the capacitance of a capacitor depend on?

Answer 26

It depends on: * The ability to generate an electric field * The dimensions of the capacitor ## Footnote Capacitance can be calculated using the formula C = εA/d.

Question 27

What is the unit of capacitance?

Answer 27

Farads (F) ## Footnote Often seen in smaller units like nanofarads (nF) or picofarads (pF).

Question 28

What happens to the permittivity when a material is placed between capacitor plates?

Answer 28

ε is replaced with εr ## Footnote εr is the relative permittivity, indicating the size of the electric field in a material compared to a vacuum.

Question 29

How do charged particles behave in a uniform electric field?

Answer 29

They move like projectiles ## Footnote A charged particle experiences a constant force F = EQ.

Question 30

What direction does a positively charged particle move in a uniform electric field?

Answer 30

In the same direction as the field lines ## Footnote This is due to the force acting on the particle being aligned with the electric field.

Question 31

What happens to a negatively charged particle in a uniform electric field?

Answer 31

It moves in the opposite direction to the field lines ## Footnote This is due to the force acting on the particle being opposite to the direction of the electric field.

Question 32

What is the work done on a charged particle by an electric field?

Answer 32

W = Fd ## Footnote This work increases the particle's kinetic energy and causes it to accelerate.

Question 33

What law describes the acceleration of a charged particle in an electric field?

Answer 33

Newton's second law ## Footnote It states that force equals mass times acceleration (F = ma).

Question 34

What remains uniform for a charged particle moving in an electric field if it has an initial velocity component at right angles to the field lines?

Answer 34

The velocity in that direction ## Footnote This is a result of Newton's first law.

Question 35

What is the combined effect of constant acceleration and constant velocity for charged particles in an electric field?

Answer 35

A curved path ## Footnote This is due to the interaction of the forces acting on the particle.