Quantum

Question 1

Excitation

Answer 1

When an electron is given enough energy to move up to a higher energy level

Question 2

Ionisation energy

Answer 2

The minimum energy required to remove the electron from the atom

Question 3

Explain how a fluorescent tube/ discharge tube works

Answer 3

-mercury vapour at low pressure
-cathode is heated causing thermionic emission
-high p.d. Is applied across the tube
-electrons accelerate cathode to anode
-collide inelastically with mercury atom
-excitation/emission
-photon of UV Emitted
-inner coatings of phosphor atoms absorb UV and emit light
-(cascades down energy levels)

Question 4

What is the photoelectric effect

Answer 4

When electromagnetic radiation is incident on the surface of a metal, the energy of a single photon is absorbed by a single electron. This electron is then released from the surface. These are called photoelectrons. Energy is conserved in this interaction.

Question 5

Wave properties

Answer 5

Diffraction and interference

Question 6

Proof of particle nature

Answer 6

Photoelectric effect

Question 7

Threshold frequency/wavelength

Answer 7

Minimum/maximum frequency/wavelength of a single photon required to release a single electron from the surface of the metal

Question 8

Work function Φ

Answer 8

Minimum energy to release an electron from the surface of the metal

Question 9

hf=

Answer 9

Φ+Ek(max)

Question 10

Stopping voltage

Answer 10

Minimum p.d required to just stop electrons being emitted from the photocathode

Question 11

Max kinetic energy of an electron emitted (using V)

Answer 11

Ek(max)= eVs

Question 12

Diffraction is greatest when

Answer 12

The wavelength and the gap the wave passes through are roughly equal

Question 13

Proof of wave properties of electrons

Answer 13

Diffracted using a thin crystal onto a phosphor screen

Question 14

de Broglie wavelength

Answer 14

λ=h/p

Question 15

eV=

Answer 15

1/2mv^2