Paper 1 Quantum Physics Drills
Q1
Quantum physics became necessary because some observations could not be explained by
A. classical wave and particle models alone.
B. Newton third law only.
C. Kirchhoff laws only.
D. ideal gas theory only.
Q2
Photon energy is given by
A. .
B. .
C. .
D. .
Q3
For light in vacuum, photon energy can also be written as
A. .
B. .
C. .
D. .
Q4
Increasing light intensity at fixed frequency mainly increases
A. energy per photon.
B. number of photons per second.
C. threshold frequency.
D. Planck constant.
Q5
In the photoelectric effect, emission can occur only if the photon frequency is
A. below threshold frequency.
B. equal to zero.
C. equal to or greater than the threshold frequency.
D. unrelated to metal.
Q6
The photoelectric equation is
A. .
B. .
C. .
D. only.
Q7
Stopping potential measures
A. maximum kinetic energy per unit charge.
B. photocurrent only.
C. threshold frequency directly.
D. work function only for all cases.
Q8
Line spectra provide evidence that atomic energy levels are
A. continuous.
B. quantised.
C. zero.
D. classical orbits only.
Q9
An emitted photon from an atom has energy equal to
A. sum of all atomic energies.
B. kinetic energy of the nucleus only.
C. zero for all transitions.
D. difference between two energy levels.
Q10
X-ray continuous spectrum is mainly due to
A. Bremsstrahlung deceleration of electrons.
B. nuclear fission.
C. alpha decay.
D. standing sound waves.
Q11
Characteristic X-ray lines depend strongly on
A. target material.
B. filament current only.
C. air pressure only.
D. slit width only.
Q12
Minimum X-ray wavelength is set by
A. target mass only.
B. detector distance only.
C. maximum electron kinetic energy.
D. line spectrum spacing only.
Q13
Electron diffraction supports the idea that electrons have
A. no momentum.
B. wave properties.
C. zero mass.
D. only charge and no energy.
Q14
de Broglie wavelength is
A. .
B. .
C. .
D. .
Q15
The uncertainty principle states that certain pairs such as position and momentum
A. can both be exactly known simultaneously.
B. have a fundamental limit on simultaneous precision.
C. are unrelated to waves.
D. apply only to planets.
Q16
A narrower wave packet usually corresponds to
A. larger spread in wavelength/momentum.
B. zero momentum spread.
C. larger certainty in both position and momentum.
D. no wave behaviour.
Q17
Which statement correctly distinguishes an absorption line from an emission line?
A. An absorption line occurs when an atom absorbs a photon whose energy matches an allowed upward transition.
B. An absorption line occurs whenever an atom absorbs a photon of any energy.
C. An emission line is produced when an electron moves to a higher energy level.
D. Emission and absorption spectra of the same element contain unrelated wavelengths.
Q18
For a particle, the minimum uncertainty product in the syllabus model is of the order of
A. .
B. for a perfect detector.
C. .
D. .
Q19
Increasing the accelerating p.d. of an X-ray tube while keeping its target unchanged causes the minimum wavelength to
A. decrease.
B. increase.
C. remain unchanged because the target is unchanged.
D. become equal to a characteristic-line wavelength.
Q20
Characteristic X-ray lines arise when
A. vacancies in inner electron shells are filled by electrons from higher levels.
B. incident electrons lose arbitrary amounts of kinetic energy while braking.
C. the filament emits visible photons.
D. the target nucleus undergoes radioactive decay.