Magentism

Question 1

State the definition of volts (3)

Answer 1

-when one joule of electric potential energy is give to one coloumb of charge
-by moving it between 2 points

1V =1J/C

Question 2

State the definition of electron volt (3)

Answer 2

-one electron volt is the energy gained by a particle
-with charge equal to the charge of an electron
-when it is accelerated through a potential difference of one volt

1V= 1.6x10^19 J

Question 3

What is thermionic emission (1)

Answer 3

When free electrons are easily produced by emission from a heated wire

Question 4

How does an electron gun function (1)

Answer 4

-the free electrons can be accelerated by applying potential difference in an evacuated tube
-producing a high velocity stream of electrons

Question 5

State the equation between KE and PE (1)

Answer 5

1/2 mv2 = e x potential difference

e = 1.6x10^-19

Question 6

Look at diagrams of electron gun and deflecting electron stream

Question 7

Explain how an electron passes through an uniform electric field (5)

Answer 7

-since it’s an electron it has a negative charge on it
-it follows a parabolic path
-the electron stream has a constant force acting on it due to electric field
-the electrons horizontal velocity is unchanged
-but vertical velocity is accelerated

Question 8

State an equation representing the force experienced by a charged particle in an electric field (2)

Answer 8

F = charge of particle x electric field strenght

Charge of particle x potential difference / distance between charges

Question 9

State the application is electron beams (1)

Answer 9

-the inkjet printer uses a deflected electron beams
-an ink gun produced 1000s of positively charged ink drops

Question 10

State how inkjet printer uses deflected electron beam (3)

Answer 10

-these ink droplets are deflected by a uniform electric field between 2 parallel plates
-the charge of the ink droplets is computer controlled but the uniform electric field is constant
-only deflected ink droplets reach the paper and each droplet is directed by using the properties of electric charge

Question 11

What are the 2 main properties of magnetism (2)

Answer 11

Field lines never cross
A magnet always has two poles

Question 12

What are lines of flux (3)

Answer 12

-the magnetic field is represented by lines of flux
-gives an indication of the strenght of the field
-the more closely they’re packed the stronger the field