Electric fields

Question 1

What is an electric field?

Answer 1

A force field where charged objects will experience a non-contact force

Question 2

Describe the interaction between like and oppositely charged particles

Answer 2

Like charges repel and oppositely charged particles attract each other.

Question 3

What is Coulomb’s law?

Answer 3

The force is directly proportional to the product of the charges of the particles and inversely proportional to their separation squared.

Question 4

What is a field line?

Answer 4

It is a line which a free positive charge would move.

Question 5

What is the electric field strength?

Answer 5

It is the force per unit charge

Question 6

Is the electric field strength a vector or a scalar and in which direction does it point?

Answer 6

Electric field strength is a vector and points in the direction that a positive charge would move

Question 7

What are the units of electric field strength?

Answer 7

Newton per coulomb N/C

Question 8

What is the relationship between the electric field strength and the distance from the point charge, in a radial field?

Answer 8

Electric field strength is inversely proportional to the distance squared

Question 9

In a uniform field, what is the relationship between the electric field strength and the distance between the plates?

Answer 9

Electric field strength is inversely proportional to the distance between the plates

Question 10

What is the direction of the force experienced by a particle as it enters a uniform electric field?

Answer 10

If positively charged, the force would act in the same direction as the field lines.
If negatively charged, the force would act in the opposite direction to the field lines.

Question 11

Describe the motion of a particle as it enters an electric field

Answer 11

The force experience by the particle causes it to accelerate perperndicular to its original motion.
The particle follows a parablic path.

Question 12

What is electric potential?

Answer 12

The work done per unit positve charge on a positive test charge when it is moved from infinity to that point

Question 13

What is the value of electric potential at an infinte distance from the point charge?

Answer 13

Zero

Question 14

What is the gradient of an electric potental against distance graph?

Answer 14

Elecctric field strength

Question 15

What is the area given under an electric field strength against distance graph?

Answer 15

Electric potential

Question 16

What is an equipotential?

Answer 16

It is a surface of constant potential

Question 17

What is there no change in potential at an equipotential?

Answer 17

No work is one because the force due to the field is perpendicular to the equipotential

Question 18

What is the potential gradient at any point in an electric field?

Answer 18

It is the change of potential per unit change of distance in a given direction

Question 19

Describe equipotentials in uniform field

Answer 19

They are equally spaced and parallel to the plates

Question 20

Describe potential gradient in a non-uniform field

Answer 20

The potential gradient varies according to position and direction. The closer the equipotentials, the greater the potential gradient perpendicular to the equipotentials

Question 21

What is the relationship between the electric field strength and the potential gradient?

Answer 21

The electric field strength is the equal to the negative of the potential gradient

Question 22

What is voltage?

Answer 22

It is defined as the work done per unit charge