WorksheetsThe electron
Total questions: 28
Worksheet time: 14mins
List two properties of an electron.
____________ named the electron and ____________ measured its charge.
(Surnames only: Newton & Einstein)
(a)
Define Thermionic Emission
Cathode Ray Tube: Where are the electrons released from?
cold metal cathode
hot metal cathode
cold metal anode
hot metal anode
List the properties of cathode rays.
- deflected by electric and magnetic fields
- cause substances to fluoresce (used to detect them)
- have kinetic energy
- travel in straight lines
- can produce x-rays when they strike a metal target
What equation gives the potential energy of the electrons in a field?
E = hf
E = 1/2 mv2
W = qV
E = mcΔΘ
Which equation gives the Kinetic energy of the electrons in an electric field?
1/2 mv2 = mgh
mcΔΘ = mgh
qV = 1/2 mv2
hf = qV
Define the electronvolt.
Give two applications of a cathode ray tube.
Define the photoelectric effect.
In a demonstration to show the photoelectric effect, why did the red light have no effect on the zinc.
It's (a) wasn't high enough.
How is the emission of electrons effected by increasing the intensity of the light.
(assuming the light has the correct frequency/energy to cause photo emission)
less electrons are given off
it is no effect at all
more electrons are given off
What relationship is found between the current and the intensity?
Assume Intensity is on the x-axis
Assume current is on the y-axis
The Threshold Frequency is the (a) frequency a photon must have to release an electron from the surface of a metal by the photoelectric effect
The Work Function is the (a) energy a photon must have to release an electron from the surface of a metal by the photoelectric effect
What is a photon?
Photon is a packet of sound energy
Photon is a packet of electromagnetic energy
Photon is a packet of kinetic energy
What is the formula for the energy of a photon?
E = mgh
E = 1/2 mv2
E = hf
E= mc2
How many electrons can one photon release?
(a)
What does the number of electrons released depend on?
Give two applications of the photoelectric effect?
What are X-Rays?
high frequency electromagnetic radiation
low-frequency electromagnetic radiation
low energy electromagnetic radiation
high energy electromagnetic radiation
short wavelength electromagnetic radiation
Who discovered x-rays?
Millikan
Roentgen
Stoney
Einstein
A _______ ________ is used to accelerate the electrons after thermionic emission in an x-ray tube.
(a)
Can X-rays be deflected by electric fields and magnetic fields?
yes
no
The energy of an x-ray depend on its (a)
List one use of x-rays in industry and one in medicine.
In the formula c=fλ , what do the symbols stand for?
c is wavelength of the wave
c is speed of the wave
f is frequency of the wave
f is wavelength of the wave
λ is wavelength of the wave
Using your formula and tables booklet, match the values to Planck's constant (h) and the speed of light (c)
h = 2.9979 x 108 ms-1
h = 6.626 x 10-34 J s
c = 2.9979 x 108 ms-1
c = 6.626 x 10-34 J s
