MCQOPTIONS
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MCQOPTIONS
This section includes 37 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
An acceptable wave function Ψ associated with a moving particle must be: |
| A. | finite, single valued and discontinuous |
| B. | finite, multiple valued and continuous |
| C. | finite, single valued and continuous |
| D. | infinite, single valued and continuous |
| Answer» D. infinite, single valued and continuous | |
| 2. |
Calculate the wavelength (in nm) of the spectral line of Balmer series for n = 3. (Rydberg constant = 1.1 × 107 m-1) |
| A. | 754 |
| B. | 854 |
| C. | 954 |
| D. | 654 |
| Answer» E. | |
| 3. |
A stationary source emits sound waves of frequency 500 Hz. Two observers moving along a line passing through the source detect sound to be of frequencies 480 Hz and 530 Hz. Their respective speeds are, in ms-1,(Given speed of sound = 300 m/s) |
| A. | 12, 16 |
| B. | 12, 18 |
| C. | 16, 14 |
| D. | 8, 18 |
| Answer» C. 16, 14 | |
| 4. |
A nucleus A, with a finite de-Broglie wavelength λA, undergoes spontaneous fission into two nuclei B and C of equal mass. B flies in the same direction as that of A, while C files in the opposite direction with a velocity equal to half of that of B. The de-Broglie wavelengths λB and λC of B and C are respectively: |
| A. | λA, 2λA |
| B. | 2λA, λA |
| C. | \({{\rm{\lambda }}_{{\rm{A'}}}}\frac{{{{\rm{\lambda }}_{\rm{A}}}}}{2}\) |
| D. | \(\frac{{{{\rm{\lambda }}_{\rm{A}}}}}{2},{{\rm{\lambda }}_{\rm{A}}}\) |
| Answer» E. | |
| 5. |
Electron emission from a metallic surface by application of light is known as |
| A. | Thermionic emission |
| B. | Photoelectric emission |
| C. | High field emission |
| D. | Auto electronic emission |
| Answer» C. High field emission | |
| 6. |
A metal surface is illuminated by a light of given intensity and frequency to cause photoemission. If the intensity of illumination is reduced to one fourth of its original value, then the maximum kinetic energy of the emitted photoelectrons would become |
| A. | unchanged |
| B. | 1/16th of original value |
| C. | twice the original value |
| D. | four times the original value |
| Answer» B. 1/16th of original value | |
| 7. |
An excited He+ ion emits two photons in succession, with wavelengths 108.5 nm and 30.4 nm, in making a transition to ground state. The quantum number n, corresponding to its initial excited state is (for photon of wavelength λ, energy \({\rm{E}} = \frac{{1240\;{\rm{eV}}}}{{\lambda \left( {{\rm{in\;nm}}} \right)}}\)) |
| A. | n = 4 |
| B. | n = 5 |
| C. | n = 7 |
| D. | n = 6 |
| Answer» C. n = 7 | |
| 8. |
A photocathode has a work function of 2.4 eV. It is illuminated with monochromatic radiation whose photon energy is 3.9 eV The maximum kinetic energy of the photoelectrons produced is: |
| A. | 2.4 × 10-19 J |
| B. | 3.7 × 10-19 J |
| C. | 4.6 × 10-19 J |
| D. | 7.2 × 10-19 J |
| Answer» B. 3.7 × 10-19 J | |
| 9. |
In the Bohr model of the hydrogen atom, let R, V and E represent the radius of the orbit, the speed of the electron and the total energy of the electron respectively. Which of the following quantity is proportional to the quantum number n? |
| A. | VR |
| B. | RE |
| C. | E / V |
| D. | R / E |
| Answer» B. RE | |
| 10. |
According to Bohr model, the radius of the electron orbit in the n = 1 level of the hydrogen atom is 0.053 nm. The radius for the n = 3 level is: |
| A. | 0.006 nm |
| B. | 0.018 nm |
| C. | 0.159 nm |
| D. | 0.477 nm |
| Answer» E. | |
| 11. |
In general, the solution of the Schrodinger wave equation is |
| A. | Real |
| B. | Imaginary |
| C. | Complex |
| D. | Complex, with real part always greater than the magnitude of the imaginary part |
| Answer» D. Complex, with real part always greater than the magnitude of the imaginary part | |
| 12. |
A team of scientists at Brookhaven National Laboratory including those from India created the heaviest anti-matter (anti-helium nucleus), What is/are the implication/implications of the creation of anti-matter?1. It will make mineral prospecting and oil exploration easier and cheaper.2. It will help probe the possibility of the existence of stars and galaxies made of anti-matter.3. It will help understand the evolution of the universe.Select the correct answer using the codes given below: |
| A. | 1 only |
| B. | 2 and 3 only |
| C. | 3 only |
| D. | 1, 2 and 3 |
| Answer» C. 3 only | |
| 13. |
A metal plate of area 1 × 10-4 m2 is illuminated by a radiation of intensity 16 m W/m2. The work function of the metal is 5 eV. The energy of the incident photons is 10 eV and only 10% of it produces photoelectrons. The number of emitted photoelectrons per second and their maximum energy, respectively will be (Take, 1 eV = 1.6 × 10-19 J) |
| A. | 1011 and 5 eV |
| B. | 1012 and 5 eV |
| C. | 1010 and 5 eV |
| D. | 1014 and 10 eV |
| Answer» B. 1012 and 5 eV | |
| 14. |
A helium-neon laser emits red light having a wavelength of 632.8 nm and a power of 0.5 mW. How many photons are emitted each second? |
| A. | 2.6 × 1018 |
| B. | 4.8 × 1017 |
| C. | 3.3 × 1016 |
| D. | 1.6 × 1015 |
| Answer» E. | |
| 15. |
If the de-Broglie wavelength of an electron is equal to 10-3 times, the wavelength of a photon of frequency 6 × 1014 Hz, then the speed of electron is equal to(Take, speed of light = 3 × 108 m/s, Planck’s constant = 6.63 × 10-34 J-s and Mass of electron = 9.1 × 10-31 kg) |
| A. | 1.45 × 106 m/s |
| B. | 1.8 × 106 m/s |
| C. | 1.1 × 106 m/s |
| D. | 1.7 × 106 m/s |
| Answer» B. 1.8 × 106 m/s | |
| 16. |
If the energy of the electron in the 2nd orbit of hydrogen is -3.4 eV, then how much is the energy (in eV) in the 1st orbit? |
| A. | -6.8 |
| B. | -1.7 |
| C. | -13.6 |
| D. | -10.2 |
| Answer» D. -10.2 | |
| 17. |
Arrange in order of the increasing vacuum work function for the below-mentioned metals:a) Aub) Nic) Agd) AlWhich of the following options is correct? |
| A. | d, c, b, a |
| B. | c, d, a, b |
| C. | b, a, c, d |
| D. | a, b, d, c |
| Answer» B. c, d, a, b | |
| 18. |
In which colour is a solar cooker painted from the outside? |
| A. | Green |
| B. | Blue |
| C. | Black |
| D. | Red |
| Answer» D. Red | |
| 19. |
If the energy of the electron in the 1st orbit of hydrogen is -13.6 eV, then how much is the energy (in eV) of an electron in the 3rd orbit? |
| A. | -1.51 |
| B. | -4.53 |
| C. | -40.8 |
| D. | -122.4 |
| Answer» B. -4.53 | |
| 20. |
In the Davisson and Germer’s experiment when 54 volts was applied to electrons, the pronounced scattering direction was found to be |
| A. | 90° |
| B. | 27° |
| C. | 108° |
| D. | 50° |
| Answer» E. | |
| 21. |
Quartz is extensively used as a piezoelectric material. It contains |
| A. | Hg |
| B. | Si |
| C. | Ti |
| D. | Sn |
| Answer» C. Ti | |
| 22. |
50 W/m2 energy density of sunlight is normally incident on the surface of a solar panel. Some part of incident energy (25%) is reflected from the surface and the rest is absorbed. The force exerted on 1m2 surface area will be close to (c = 3 × 108 m/s): |
| A. | 15 × 10-8 N |
| B. | 20 × 10 -8 N |
| C. | 10 × 10-8 N |
| D. | 35 × 10-8 N |
| Answer» C. 10 × 10-8 N | |
| 23. |
Consider an electron in a hydrogen atom, revolving in its second excited state (having radius 4.65 Å). The de-Broglie wavelength of this electron is: |
| A. | 3.5 Å |
| B. | 6.6 Å |
| C. | 12.9 Å |
| D. | 9.7 Å |
| Answer» E. | |
| 24. |
If the radius of the 1st orbit of hydrogen is 'r', then the radius of the 3rd orbit of hydrogen is ________. |
| A. | 9r |
| B. | r1 / 3 |
| C. | 3r |
| D. | r3 |
| Answer» B. r1 / 3 | |
| 25. |
According to Hamilton's least action principle, the quantity that is minimized is |
| A. | \(\smallint \left( {T - V} \right)dt\) |
| B. | \(\smallint \left( {T + V} \right)dt\) |
| C. | \(\smallint \left( {\frac{T}{V}} \right)dt\) |
| D. | \(\smallint \left( {T\times V} \right)dt\) |
| Answer» B. \(\smallint \left( {T + V} \right)dt\) | |
| 26. |
A ruby laser delivers a 10 ns pulse of 1 MW average power. If all the photons are of the same wavelength 694.3 nm, how many photons are contained in the pulse? |
| A. | 3.5 × 1016 |
| B. | 6.2 × 1016 |
| C. | 2.6 × 1015 |
| D. | 4.0 × 1014 |
| Answer» B. 6.2 × 1016 | |
| 27. |
A light beam is incident on a metal target with a work function of 2.3 eV. If a stopping potential of 1.3 V is required, what is the wavelength of the incident light? (h = 6.63 × 10-34 J s, c = 3 × 108 m/s, 1 eV = 1.6 × 10-19 J): |
| A. | 76 nm |
| B. | 345 nm |
| C. | 487 nm |
| D. | 1411 nm |
| Answer» C. 487 nm | |
| 28. |
In a photoelectric effect experiment the threshold wavelength of light is 380 nm. If the wavelength of incident light is 260 nm, the maximum kinetic energy of emitted electrons will be:Given E (in eV) \(=\frac{{1237}}{{\lambda {\rm{\;}}\left( {in{\rm{\;}}nm} \right)}}\) |
| A. | 1.5 eV |
| B. | 3.0 eV |
| C. | 4.5 eV |
| D. | 15.1 eV |
| Answer» B. 3.0 eV | |
| 29. |
According to quantum mechanics, a moving material particle is associated with: |
| A. | a wave packet |
| B. | light wave |
| C. | a single wave |
| D. | acoustic wave |
| Answer» B. light wave | |
| 30. |
As the quantum number increases, the difference of energy between successive energy levels |
| A. | Remains unchanged |
| B. | Increases |
| C. | decreases |
| D. | First increases then decreases |
| Answer» D. First increases then decreases | |
| 31. |
Isotope of Hydrogen that has mass number 2 |
| A. | Protium |
| B. | Tritium |
| C. | Deuterium |
| D. | None of these |
| Answer» D. None of these | |
| 32. |
Light of wavelength 450 nm is incident on a metal target (work function = 1.8 eV) in a phototube. What is the value of stopping potential in this case?(h = 6.63 × 10-34J s, c = 3 × 108 m/s, 1 eV = 1.6 × 10-19 J) |
| A. | 4.56 V |
| B. | 0.96 V |
| C. | 2.76 V |
| D. | 0.56 V |
| Answer» C. 2.76 V | |
| 33. |
Necessary condition for photo-electric emission is: |
| A. | hν ≥ eϕ |
| B. | hν ≥ mc |
| C. | hν ≥ eϕ2 |
| D. | \(hν ≥ \frac{1}{2}mc\) |
| Answer» B. hν ≥ mc | |
| 34. |
In a photoelectric experiment, the wavelength of the light incident on a metal is changed from 300 nm to 400 nm. The decrease in the stopping potential is close to \(\left( {\frac{{hc}}{e} = 1240{\rm{n}}\cdot{\rm{mV}}} \right)\) |
| A. | 0.5V |
| B. | 2.0V |
| C. | 1.5 V |
| D. | 1.0 V |
| Answer» E. | |
| 35. |
If T and V represent the kinetic and potential energies of a body respectively the Hamiltonian is given by |
| A. | T - V |
| B. | T + V |
| C. | T/V |
| D. | T × V |
| Answer» C. T/V | |
| 36. |
If the radius of the 1st orbit of hydrogen is 5.29 × 10-11 m, then the radius of the 2nd orbit of hydrogen is ________ × 10-11 m. |
| A. | 10.58 |
| B. | 2.645 |
| C. | 21.16 |
| D. | 27.98 |
| Answer» D. 27.98 | |
| 37. |
If the energy of the electron in the 2nd orbit of hydrogen is -3.4 eV, then how much is the energy (in eV) in the 3rd orbit? |
| A. | - 1.511 |
| B. | 2.22 |
| C. | - 5.1 |
| D. | -13.6 |
| Answer» B. 2.22 | |