Electric Fields

Question 1

What is Coulomb’s Law in words?

Answer 1

The force between two positive charges is
Proportional to the product of their charge
Inversely proportional to the square of their distance apart

Question 2

What is the equation for Coulomb’s Law?

Answer 2

F=1/(4πε) Qq/r²

Question 3

What is 1/(4πε)?

Answer 3

Electric Field constant/multiplier

ε is the Permittivity of free space (8.98x10^9)

Question 4

What is an Electric Field?

Answer 4

The force acting on a unit positive charge

Question 5

What are the units of an Electric Field?

Answer 5

Newtons per Coulomb (NC^-1)
or
Volts per Meter (Vm^-1)

Question 6

What equation is the defintion of an Electric Field?

Answer 6

E=F/Q

Question 7

What equation is used to calculate the strength of an Electric Field at a point?

Answer 7

E=1/(4πε) Q/r²

Question 8

Where is the Electric Field strongest on a sphere?

Answer 8

On the surface

Question 9

What is the Electric Field inside a sphere?

Answer 9

Zero

Question 10

Is an Electric Field a scalar or vector?

Answer 10

Vector

Question 11

Which way do Electric Field lines point?

Answer 11

Away form positve

Towards Negative

Question 12

What does the magnitude of the Electric Field depend on?

Answer 12

The charge creating the field

Question 13

What is E proportional to?

Answer 13

Q

Question 14

What is E inversely proportional to?

Answer 14

r²

Question 15

What are the units of Electric Potential Energy?

Answer 15

Joules (J)

Question 16

What is the definition of Electric Potential Energy?

Answer 16

The work done in moving a charge from infinity to a distance (r) within the Electric Field

Question 17

What is the equation for calculating Electric Potential Energy?

Answer 17

W=1/(4πε) Qq/r

not on data sheet

Question 18

What is W proportional to?

Answer 18

Qq

Question 19

What is W inversely proportional to ?

Answer 19

r

Question 20

What is the equation for calculating the change in Electric Potential Energy?

Answer 20

ΔW=Qq/(4πε) (1/r(2) - 1/r(1))

Question 21

What are the units for Electric Potentials?

Answer 21

Joules per Coulomb (JC^-1)
or
Volts (V)

Question 22

What is the definition of Electric Potentials?

Answer 22

The work done in moving a unit positive charge from infinity to a distance r within an Electric Field

Question 23

What is the definition of Electric Potentials as an equation?

Answer 23

V=W/Q

Question 24

What is the equation for calculating Electric Potentials?

Answer 24

V=1/(4πε) Q/r

(As Electric Potentials is the same as Electric potential energys but for a unit positve charge, imagine
1/(4πε) Qq/r with q=1 as q is a unit positive charge)

Question 25

Are Electric Potential Energies positive or Negative?

Answer 25

``` They are both Q q W + - = - + + = + - - =+ ```

Question 26

Are Electric Potentials positive or negative?

Answer 26

They can be either A positive charge produces a positve potential A negative charge produces a negative potential

Question 27

What is an Equipotential?

Answer 27

Lines joining points of equal potential | They are always perpendicular to field lines

Question 28

What is the Electric potenial within a sphere?

Answer 28

The same as the surface as energy has been used to move the coulomb to the surface therefore to conserve energy it must be the same as no additional work is doen within the sphere

Question 29

Where is the greatest Electric Potential on a sphere?

Answer 29

On the surface

Question 30

What is the gradient on a potential-distance graph?

Answer 30

The Field strength at that radius

Question 31

What equation links Electric Fields, Potential Difference and Distance?

Answer 31

E=-ΔV/Δr

Question 32

What is a Uniform Electric Field?

Answer 32

A field btween two metal plates with a p.d across them\

Question 33

What equation is used to calulate the strength of a Uniform Electric Field?

Answer 33

E=V/d

Question 34

How do you calculate the acceleration due to a Uniform Electric Field?

Answer 34

a=VQ/dm

Question 35

What is the total charge of an Uniform Electric Field?

Answer 35

0

Question 36

How is motion in a Uniform Electric Field modeled?

Answer 36

projectile motion

Question 37

What type of current is present in a the shuttle ball experiment?

Answer 37

DC | As the ball transfers a small amount of charge from plate to plate.