Physics Trivia Questions for College Students

An organ pipe, closed at one end and open at the other, is designed to have a fundamental frequency of C (131 Hz). What is the frequency of the next higher harmonic for this pipe?

• A262 Hz
• B196 Hz
• C44 Hz
• D393 Hz

Sound waves moving at 350 m/s diffract out of a speaker enclosure with an opening that is a long rectangular slit 0.14 m across. At about what frequency will the sound first disappear at an angle of 45q from the normal to the speaker face?

• A3,500 Hz
• B2,750 Hz
• C500 Hz
• D1,750 Hz

An object is thrown horizontally from the open window of a building. If the initial speed of the object is 20 m/s and it hits the ground 2.0 s later, from what height was it thrown? (Neglect air resistance and assume the ground is level.)

• A19.6 m
• B10.0 m
• C4.9 m
• D9.8 m

A 3-microfarad capacitor is connected in series with a 6-microfarad capacitor. When a 300-volt potential difference is applied across this combination, the total energy stored in the two capacitors is

• A0.09 J
• B0.18 J
• C0.41 J
• D0.27 J

A uniform solid disk starts from rest and rolls down an inclined plane without slipping. After some time, what fraction of the disk's total kinetic energy is rotational kinetic energy?

• A1/4
• B2/3
• C1/2
• D1/3

The eigenvalues of a Hermitian operator are always

• Aimaginary
• Blinear
• Cdegenerate
• Dreal

The rest mass of a particle with total energy 5.0 GeV and momentum 4.9 GeV/c is approximately

• A1.0 GeV/c^2
• B0.2 GeV/c^2
• C0.5 GeV/c^2
• D0.1 GeV/c^2

Which of the following lasers utilizes transitions that involve the energy levels of free atoms?

• AFree-electron laser
• BDiode laser
• CDye laser
• DGas laser

Characteristic X rays, appearing as sharp lines on a continuous background, are produced when high-energy electrons bombard a metal target. Which of the following processes results in the characteristic X rays?

• AElectrons filling inner shell vacancies that are created in the metal atoms
• BElectrons colliding with phonons in the metal
• CElectrons producing Čerenkov radiation
• DElectrons combining with protons to form neutrons

The coefficient of static friction between a small coin and the surface of a turntable is 0.30. The turntable rotates at 33.3 revolutions per minute. What is the maximum distance from the center of the turntable at which the coin will not slide?

• A0.121 m
• B0.242 m
• C0.024 m
• D0.048 m

If the total energy of a particle of mass m is equal to twice its rest energy, then the magnitude of the particle's relativistic momentum is

• A(3^(1/2))mc
• Bmc
• Cmc/2
• Dmc/(2^(1/2))

A tube of water is traveling at 1/2 c relative to the lab frame when a beam of light traveling in the same direction as the tube enters it. What is the speed of light in the water relative to the lab frame? (The index of refraction of water is 4/3.)

• A1/2 c
• B5/6 c
• C2/3 c
• D10/11 c

Protons used in cancer therapy are typically accelerated to about 0.6c. How much work must be done on a particle of mass m in order for it to reach this speed, assuming it starts at rest?

• A0.60mc^2
• B0.25mc^2
• C1.25mc^2
• D0.67mc^2

The emission spectrum of the doubly ionized lithium atom Li++ (Z = 3, A = 7) is identical to that of a hydrogen atom in which all the wavelengths are

• Adecreased by a factor of 49
• Bincreased by a factor of 9
• Cdecreased by a factor of 9
• Ddecreased by a factor of 81

The negative muon, mu^-, has properties most similar to which of the following?

• AElectron
• BMeson
• CBoson
• DPhoton

At the present time, the temperature of the universe (i.e., the microwave radiation background) is about 3 K. When the temperature was 12 K, typical objects in the universe, such as galaxies, were

• Atwo times as distant as they are today
• Bone-quarter as distant as they are today
• Cone-half as distant as they are today
• Dseparated by about the same distances as they are today

According to the BCS theory, the attraction between Cooper pairs in a superconductor is due to

• Athe weak nuclear force
• Bthe strong nuclear force
• Cvacuum polarization
• Dinteractions with the ionic lattice

In the diamond structure of elemental carbon, the nearest neighbors of each C atom lie at the corners of a

• Acube
• Btetrahedron
• Csquare
• Dhexagon

De Broglie hypothesized that the linear momentum and wavelength of a free massive particle are related by which of the following constants?

• AThe Rydberg constant
• BPlanck's constant
• CBoltzmann's constant
• DThe speed of light

The muon decays with a characteristic lifetime of about 10^-6 second into an electron, a muon neutrino, and an electron antineutrino. The muon is forbidden from decaying into an electron and just a single neutrino by the law of conservation of

• Aenergy and momentum
• Blepton number
• Ccharge
• Dmass

A heat pump is to extract heat from an outdoor environment at 7°C and heat the environment indoors to 27°C. For each 15,000 J of heat delivered indoors, the smallest amount of work that must be supplied to the heat pump is approximately

• A500 J
• B1,000 J
• C2,000 J
• D1,100 J

White light is normally incident on a puddle of water (index of refraction 1.33). A thin (500 nm) layer of oil (index of refraction 1.5) floats on the surface of the puddle. Of the following, the most strongly reflected wavelength is

• A500 nm
• B600 nm
• C550 nm
• D650 nm

Under ideal conditions, the electric and magnetic fields inside a superconductor are zero. Maxwell's equations imply that which of the following must be true just outside the surface of the superconductor?

• AB is tangential to the surface.
• BB is perpendicular to the surface.
• CB = 0
• DB is time independent.

Electromagnetic radiation emitted from a nucleus is most likely to be in the form of

• Agamma rays
• Bultraviolet radiation
• Cvisible light
• Dmicrowaves

Which of the following is true about any system that undergoes a reversible thermodynamic process?

• AThe temperature of the system remains constant during the process.
• BThe entropy of the system and its environment must increase.
• CThe entropy of the system and its environment remains unchanged.
• DThere are no changes in the internal energy of the system.

The sign of the charge carriers in a doped semiconductor can be deduced by measuring which of the following properties?

• ASpecific heat
• BElectrical resistivity
• CHall coefficient
• DThermal conductivity

The first five harmonics produced by an organ pipe open at both ends are 50 Hz, 100 Hz, 150 Hz, 200 Hz, and 250 Hz. Which of the harmonics, if any, will survive once the pipe is closed at one end?

• A50 Hz, 150 Hz, and 250 Hz only
• BNone
• C150 Hz and 250 Hz only
• D100 Hz and 200 Hz only

A refracting telescope consists of two converging lenses separated by 100 cm. The eye-piece lens has a focal length of 20 cm. The angular magnification of the telescope is

• A5
• B4
• C6
• D20

At 20°C, a pipe open at both ends resonates at a frequency of 440 hertz. At what frequency does the same pipe resonate on a particularly cold day when the speed of sound is 3 percent lower than it would be at 20°C ?

• A433 Hz
• B427 Hz
• C440 Hz
• D414 Hz

The primary source of the Sun's energy is a series of thermonuclear reactions in which the energy produced is c^2 times the mass difference between

• Afour hydrogen atoms and one helium atom
• Bsix hydrogen atoms and two helium atoms
• Cthree helium atoms and one carbon atom
• Dtwo hydrogen atoms and one helium atom

For which of the following thermodynamic processes is the increase in the internal energy of an ideal gas equal to the heat added to the gas?

• AConstant temperature
• BAdiabatic
• CConstant pressure
• DConstant volume

If the absolute temperature of a blackbody is increased by a factor of 3, the energy radiated per second per unit area does which of the following?

• AIncreases by a factor of 81.
• BDecreases by a factor of 81.
• CDecreases by a factor of 9.
• DIncreases by a factor of 9.

Which of the following ions CANNOT be used as a dopant in germanium to make an n-type semiconductor?

• AP
• BSb
• CAs
• DB

In a nonrelativistic, one-dimensional collision, a particle of mass 2m collides with a particle of mass m at rest. If the particles stick together after the collision, what fraction of the initial kinetic energy is lost in the collision?

• A0
• B1/3
• C1/4
• D1/2

If the Sun were suddenly replaced by a black hole of the same mass, it would have a Schwarzschild radius of 3,000 m. What effect, if any, would this change have on the orbits of the planets?

• AThe planets would move in spiral orbits.
• BThe orbits would remain unchanged.
• CThe planets would oscillate about their former elliptical orbits.
• DThe planets would move directly toward the Sun.

An astronomer observes a very small moon orbiting a planet and measures the moon's minimum and maximum distances from the planet's center and the moon's maximum orbital speed. Which of the following CANNOT be calculated from these measurements?

• AMinimum speed of the moon
• BMass of the planet
• CMass of the moon
• DPeriod of the orbit

A meter stick with a speed of 0.8c moves past an observer. In the observer's reference frame, how long does it take the stick to pass the observer ?

• A6.9 ns
• B2.5 ns
• C1.6 ns
• D4.2 ns

The speed of light inside of a nonmagnetic dielectric material with a dielectric constant of 4.0 is

• A3.0 x 10^8 m/s
• B1.5 x 10^8 m/s
• C1.0 x 10^8 m/s
• D1.2 x 10^9 m/s

A spring of force constant k is stretched a certain distance. It takes twice as much work to stretch a second spring by half this distance. The force constant of the second spring is

• Ak
• B4k
• C2k
• D8k

Which of the following statements about bosons and/or fermions is true?

• ABosons have symmetric wave functions and obey the Pauli exclusion principle.
• BFermions have antisymmetric wave functions and obey the Pauli exclusion principle.
• CFermions have symmetric wave functions and obey the Pauli exclusion principle.
• DBosons have antisymmetric wave functions and do not obey the Pauli exclusion principle.

Assume that the solar flux at Earth's surface is 1,000 W/m^2 and that the sunlight is normal to a completely reflecting surface with an area of 3 m^2. What is the total radiation force exerted on the surface?

• A3 N
• B2 x 10^-5 N
• C1 x 10^-5 N
• D2 x 10^-6 N

By definition, the electric displacement current through a surface S is proportional to the

• Arate of change of the electric flux through S
• Brate of change of the magnetic flux through S
• Cmagnetic flux through S
• Dtime integral of the magnetic flux through S

Unpolarized light is incident on a pair of ideal linear polarizers whose transmission axes make an angle of 45q with each other. The transmitted light intensity through both polarizers is what percentage of the incident intensity?

• A100%
• B25%
• C75%
• D50%

A particle decays in 2.0 ms in its rest frame. If the same particle moves at v=0.60c in the lab frame, how far will it travel in the lab before decaying?

• A150 m
• B288 m
• C360 m
• D450 m

A magnetic field is directed perpendicular to the plane of a circular coil of area 0.2 m^2 and 250 turns. If the magnetic field is increased from 0.01 T to 0.06 T during a time interval of 0.25 s, the average induced EMF in the coil is

• A10 V
• B2.5 V
• C0.04 V
• D0.1 V

A grating spectrometer can just barely resolve two wavelengths of 500 nm and 502 nm, respectively. Which of the following gives the resolving power of the spectrometer?

• A250
• B5,000
• C2
• D10,000

A three-dimensional harmonic oscillator is in thermal equilibrium with a temperature reservoir at temperature T. The average total energy of the oscillator is

• A3kT
• BkT
• C(3/2) k T
• D(1/2) k T

The mean kinetic energy of the conduction electrons in metals is ordinarily much higher than kT because

• Athe electrons and the lattice are not in thermal equilibrium
• Bthe electrons form a degenerate Fermi gas
• Celectrons have many more degrees of freedom than atoms do
• Delectrons in metals are highly relativistic

A rod measures 1.00 m in its rest system. How fast must an observer move parallel to the rod to measure its length to be 0.80 m?

• A0.50c
• B0.60c
• C0.70c
• D0.80c

Consider an electron in the n = 4, l = 1 state in hydrogen. Which of the following final states can NOT be reached by an allowed transition?

• An = 3, l = 2
• Bn = 3, l = 0
• Cn = 3, l = 1
• Dn = 2, l = 0