Quantum Physics

Question 1

Single slit experiment: expect with particles

Answer 1

Zero hits in shadow region

Question 2

Single slit experiment particle: observed

Answer 2

Particles hit shadow region

F=ma failed

Question 3

Single slit experiment: large p affects spread how

Answer 3

Smaller spread

Question 4

Single slit experiment: large wavelength affects spread how?

Answer 4

Larger spread

Question 5

Double slit: expect

Answer 5

One big interference pattern (one large bump)

Question 6

Double slit: observe

Answer 6

Many lumps (like a sin wave lol)
P = P1 + P2 + interference terms

Question 7

Photoelectric effect: wave (3)

Answer 7

1) happens for any f provided A^2t is large enough
2) need A^2t > w, measurable time delay
3) kmax proportional to A^2, more intense light increases Kmax

All wrong

Question 8

Photoelectric effect: particle (3)

Answer 8

1) minimum threshold frequency indep of A, t
2) instantaneous (particle collision)
3) completely indep of light intensity

Question 9

How is all light created

Answer 9

Accelerated electric charge

Question 10

X-Ray production: wave

Answer 10

Light of all frequencies produced

Wrong

Question 11

X-Ray production: particle

Answer 11

Only light with f less than F max produced

Question 12

Why do you have an atomic nucleus in pair production

Answer 12

For momentum conservation

If not, how can two particles momentum = c?

Question 13

Chemical reaction energy is about

Answer 13

1eV

Question 14

Nuclear reaction energy is about

Answer 14

1 MeV

Question 15

Blackbody radiation

Answer 15

Closed box at T, atoms vibrate emitting EM waves in thermal equilibrium
Waves can be thought of as superposition of many em standing waves with random fluctuating amplitude and phase, maintain thermal eq via walls

Question 16

Ultraviolet catastrophe

Answer 16

Wave model fails

Frequency should just continue to go up with more intensity and stuff, but it doesn’t be particle

Question 17

Static model of the atom

Answer 17

Electrostatic forces hold it together

Question 18

Problems with the static model

Answer 18

The attractive force would cause acceleration and electron would lose em waves as energy and collapse

Question 19

Dynamic model of the atom

Answer 19

Like planets orbiting sun

Question 20

Problems with dynamic model

Answer 20

Same as static - centripetal acceleration is still acceleration
Now they have a fun spiral

Question 21

Why doesn’t electron cloud exist

Answer 21

Electrostatic repulsion of parts of electron would change energy levels in not observed ways
Instead electron is point particle that behaves like wave

Question 22

How does the stationary state fix the atom problem

Answer 22

Rotating ring of charge instead of point charge

Creates steady current loop and magnetic field instead