Physics 12 - Unit 5 Quiz

Name:

True/False

Indicate whether the sentence or statement is true or false.

The time interval separating two events is not absolute but relative to the choice of inertial frame.

It is possible for a particle with a nonzero rest mass to be accelerated to the speed of light.

Rest energy, the product of c² and rest mass, can be converted into other forms of energy.

Photoelectrons are emitted from a photoelectric material when the frequency of the incident light exceeds the threshold frequency of the material.

In the photoelectric effect, the intensity of the incident light does not affect the threshold frequency.

The cutoff potential measures the maximum kinetic energy with which photoelectrons are emitted.

Coulomb’s law, F_e =

, does not apply to the forces between charged particles at distances smaller than the size of atoms.

The Franck–Hertz experiment revealed that the energy of incident electrons is absorbed by mercury atoms only at discrete energy levels.

An particle is also called a hydrogen nucleus.

10.

The neutrino was suggested to resolve the problem of conserving energy and momentum in

decay.

11.

For any given energy, less synchrotron radiation results in an accelerator when less massive particles are used.

12.

The strong nuclear force can be attractive or repulsive.

13.

Because the particles that mediate the weak force are relatively massive, the force acts over a relatively short distance.

14.

All hadrons are leptons or mesons.

15.

The standard model accounts for every observed particle.

16.

Symmetry is frequently applied to scientific theories to predict previously unobserved events.

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

17.

You and your friend are in separate spaceships. In the inertial frame of your ship, your friend recedes from you at 0.9999c. If you point a laser beam at your friend, and your friend points a laser beam at you, then

a.	each of you sees laser light arrive at a speed of c
b.	each of you sees laser light arrive at a speed of 2c
c.	neither of you sees light from the other’s laser
d.	one of you sees laser light arrive at a speed of c, while the other sees laser light arrive at a speed of 2c
e.	none of these propositions is true

18.

A clock, designed to tick once a second, is in a spaceship moving at a constant speed of 0.5c through an inertial frame. You find that the clock is

a.	ticking once a second
b.	ticking at a rate faster than once a second
c.	ticking at a rate slower than once a second
d.	running backward
e.	none of these

19.

Classical physics offered a satisfactory explanation for

a.	the deflection of charged particles in an electric field
b.	the diffraction of electrons by crystals
c.	the intensity spectrum of blackbody radiation
d.	the photoelectric effect
e.	matter waves

20.

When investigating

decay, the neutrino was postulated to explain

a.	conservation of energy and momentum
b.	conservation of the number of nucleons
c.	counteracting the ionizing effect of radiation
d.	the production of antiparticles
e.	the energy to carry away the particle

21.

Gamma radiation differs from and

emissions in that

a.	it consists of photons rather than particles having nonzero rest mass
b.	it has almost no penetrating ability
c.	energy is not conserved in the nuclear decays producing it
d.	momentum is not conserved in the nuclear decays producing it
e.	it is not produced in the nucleus

22.

How could you distinguish between and

particles in a cloud chamber?

a.	It would be trivial since only particles produce visible tracks.
b.	It would be trivial since only particles produce visible tracks.
c.	It would be impossible to do.
d.	The particles tend to produce double trails.
e.	The particles bend in opposite directions in a magnetic field.

23.

The Feynman diagram in Figure 1 illustrates

Figure 1

a.	⁺ decay
b.	^- decay
c.	decay
d.	pair production
e.	annihilation

24.

The quantum quantity called strangeness was postulated because observation revealed

a.	opposite charges and production in pairs
b.	unexpectedly long decay times and production in pairs
c.	unexpectedly long decay times and opposite charges
d.	unexpectedly high spin numbers and opposite charges
e.	unexpectedly low spin numbers and unexpectedly long decay times

25.

An example of an impossible quark combination is

a.	uud
b.	udd
c.	uuu
d.	ud
e.	us

Completion

Complete each sentence or statement.

26.

Any frame of reference in which the law of inertia holds is called a(n) _______ frame.

27.

Any frame in which the law of inertia does not hold is called a(n) _______ frame.

28.

Michelson and Morley’s interferometer experiment showed that _______ .

29.

According to the effects of length contraction, a body contracts along the direction of its _______ .

30.

The only mass that can be measured directly is _______ .

31.

Planck proposed that energy is radiated in discrete bundles called _______ .

32.

The threshold frequency for photoelectron emission from a photoelectric material is _______ (the same, different) for different metals.

33.

The higher the frequency of the light, the _______ (higher, lower) the cutoff potential.

34.

Matter waves predict the _______ that a particle will follow a particular path.

35.

A 4.0-eV photon is absorbed by a metal surface with threshold energy 3.0 eV. An electron can be emitted with a kinetic energy in the range of _______ eV to _______ eV.

36.

A continuous spectrum is produced by _______ . An emission spectrum is produced by _______ .

37.

In the Rutherford scattering experiment, particles were beamed at a thin gold foil. After encountering the gold foil, most of the particles were _______ .

38.

As the electron in a hydrogen atom passes from a higher to a lower orbital, its orbital radius _______ (increases, decreases), its speed _______ (increases, decreases), and its energy _______ (increases, decreases).

39.

The half-life, in years, for the decay represented by the graph in Figure 2 is _______ .

Figure 2

40.

We can determine whether a given particle is a meson or a baryon once we know its _______ .

Matching

Match the scientist to the discovery or innovation.

a.	Rutherford	g.	Planck
b.	Davisson	h.	Einstein
c.	Bohr	i.	Franck
d.	Compton	j.	Heisenberg
e.	Becquerel	k.	Gell-Mann
f.	de Broglie

41.

-scattering experiment

42.

radioactivity

43.

diffraction of particle

44.

energy levels and orbitals in the hydrogen atom

45.

energy levels in an excited gas

46.

matter waves

47.

particle classification

48.

momentum of a photon

49.

photoelectric effect

50.

planetary model of the atom

51.

quanta

52.

uncertainty