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Flashcards in Electric Fields Deck (35)
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1

What is an electric field associated to?

Charge

2

Define electric field strength

The force that would act on a unit charge placed at a point in the field.

3

What is the relationship between electric field strength and the distance?

E ∝ 1/r^2

4

What is the pattern of electric field lines?

Radial

5

What is the direction of an electric field?

The direction of the force that would act on a positive charge placed in the field.

6

Give two factors that can affect the size of the electric field between two plates.

- The pd across the plates.
- The plate separation.

7

What is the relationship between electric field strength and the position between the plates?

They are independent

8

What is the relationship between electric field strength and the pd across the plates?

E ∝ V

9

What is the relationship between electric field strength and the separation of the plates?

E ∝ 1/d

10

When does the formula E=V/d apply?

When two plates are parallel

11

When does an electric field do work on a positive charge?

When the charge moves in the direction of the electric field.

12

What is the relationship between electric field lines and equipotential surfaces?

They are perpendicular to each other.

13

What is the relationship between field strength and potential?

Field strength = -Potential gradient (-dV/dx)

14

What is the relationship between potential and charge?

V ∝ Q

15

What is the relationship between potential and distance?

V ∝ 1/r

16

How is potential calculated?

V = (1/4πε0)(Q/r)

17

What is ε0?

The permittivity of free space

18

How is the potential at the surface of a sphere calculated?

V = (1/4πε0)(Q/a)

19

How is electrical potential energy calculated?

EPE = qV

20

What does a negative EPE show?

An attractive system

21

How is electric field strength in a radial field calculated?

E = (1/4πε0)(Q/r^2)

22

How is the force between two objects calculated?

F = (1/4πε0)(Qq/r^2)

23

Is field potential scalar of vector?

Scalar

24

Is field strength scalar or vector?

Vector

25

What is the unit of W?

Joules

26

When is work done by the field?

When W is negative

27

When is work done against the field?

When W is positive

28

How is work done calculated?

W = qΔV

29

How is the force on a charge in an electric field calculated?

F = qE

30

When is the force of an electric field positive?

When the force is repulsive