MCQOPTIONS
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MCQOPTIONS
This section includes 39 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Bracket series is obtained when all transition of electron terminate on |
| A. | 4th orbit |
| B. | 5th orbit |
| C. | 3rd orbit |
| D. | 2nd orbit |
| Answer» B. 5th orbit | |
| 2. |
Electron cannot exist in the nucleus it is confirmed by observing that |
| A. | It does emit ?-radiation. |
| B. | Its size as compare to proton and neutron is very small. |
| C. | No antiparticle of electron is present. |
| D. | The velocity of electron must be very high according to uncertainty principle. |
| Answer» E. | |
| 3. |
In an electronic transition atom cannot emit |
| A. | ?-rays |
| B. | Infra red radiation |
| C. | Visible light |
| D. | Ultraviolet rays |
| Answer» B. Infra red radiation | |
| 4. |
Excited atoms return to their ground state in |
| A. | 10-10s |
| B. | 10-8s |
| C. | 10-6s |
| D. | 10-9s |
| Answer» C. 10-6s | |
| 5. |
Hydrogen atom does not emit X-rays because |
| A. | Its energy levels are too close to each other |
| B. | Its energy levels are too far apart |
| C. | It is too small in size |
| D. | It has a single electron |
| Answer» E. | |
| 6. |
Ground state energy of the 4th orbit in a H-atom is |
| A. | ?13.60 eV |
| B. | ?3.40 eV |
| C. | ?0.85 eV |
| D. | ?1.51 eV |
| Answer» D. ?1.51 eV | |
| 7. |
In an X-ray tube electrons each of charge e are accelerated through V potential difference allowed to hit a metal target. The wavelength of the X-rays emitted is |
| A. | He/ev |
| B. | He/Vc |
| C. | EV/h |
| D. | Impossible to predict |
| Answer» B. He/Vc | |
| 8. |
Total number of series in hydrogen spectrum is |
| A. | Three |
| B. | Four |
| C. | Five |
| D. | Six |
| Answer» D. Six | |
| 9. |
UV radiation can be produced by |
| A. | Heating the filament. |
| B. | Electron excitation in the gas. |
| C. | Ionization of atoms. |
| D. | All the above. |
| Answer» C. Ionization of atoms. | |
| 10. |
Wave-like characteristic of electron is demonstrated by |
| A. | Line spectrum of atoms. |
| B. | Production of x-rays. |
| C. | Diffraction by crystalline solids. |
| D. | Photoelectric effect. |
| Answer» D. Photoelectric effect. | |
| 11. |
What is the velocity of a particle of mass m & de-Broglie wavelength ?? |
| A. | H/m? |
| B. | 2h/m? |
| C. | Mh/h |
| D. | (2hc/m?)1/2 |
| Answer» B. 2h/m? | |
| 12. |
When we excite some atoms by heat collision or electrical discharge they will |
| A. | Radiate electromagnetic energy with a continuous distribution of wavelength |
| B. | Absorb particular wavelengths when white light is incident on them |
| C. | Radiate electromagnetic energy of discrete characteristic wavelength |
| D. | Emit either invisible or visible light |
| Answer» D. Emit either invisible or visible light | |
| 13. |
When X-rays are passed through successive aluminum sheets what happens to their thickness? |
| A. | Increases |
| B. | It decreases |
| C. | It remains same |
| D. | Sometimes increases and sometimes decreases |
| Answer» D. Sometimes increases and sometimes decreases | |
| 14. |
Which one of following postulate is in accordance with the Rutherfords model? |
| A. | Continuous spectra for atoms |
| B. | Discrete spectra for atoms |
| C. | Either continuous nor discrete |
| D. | No spectrum |
| Answer» B. Discrete spectra for atoms | |
| 15. |
X-ray are |
| A. | Of unknown nature |
| B. | High energy electrons |
| C. | High energy photons |
| D. | Radio isotopes |
| Answer» D. Radio isotopes | |
| 16. |
X-rays are diffracted by a crystal but not by a diffraction grating because |
| A. | The ions in a crystal are well arranged. |
| B. | The lines in a diffraction grating cannot reflect X-rays. |
| C. | The penetration power of X-rays is high in a diffraction grating. |
| D. | The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal |
| Answer» E. | |
| 17. |
X-rays are similar in nature to |
| A. | Cathode rays |
| B. | Positive rays |
| C. | ?-rays |
| D. | ?-rays |
| Answer» D. ?-rays | |
| 18. |
Radiation produced from TV picture tube is |
| A. | ?-rays |
| B. | X-rays |
| C. | Far infrared. |
| D. | Infrared |
| Answer» C. Far infrared. | |
| 19. |
Ratio of the weight of H-atom to that of an electron is approximately |
| A. | 18.336 |
| B. | 1836 |
| C. | 18360 |
| D. | 183.6 |
| Answer» C. 18360 | |
| 20. |
Radiation with wavelength longer than red lights |
| A. | Ultraviolet rays |
| B. | X-rays |
| C. | Infra red radiation |
| D. | Visible radiation |
| Answer» D. Visible radiation | |
| 21. |
The minimum wavelength of X-rays produced by the bombardment of electrons on the screen of a television set where the accelerating potential is 2.0K V will be |
| A. | 6.2 x 10-10m |
| B. | 9.1 x 10-18m |
| C. | 3.11 x 10-10m |
| D. | 4 x 10-10m |
| Answer» B. 9.1 x 10-18m | |
| 22. |
Reverse process of photoelectric effect is |
| A. | Pair production |
| B. | Compton effect |
| C. | Annihilation of matter |
| D. | X-rays production |
| Answer» E. | |
| 23. |
Reflecting mirrors in laser is used to |
| A. | Further stimulation |
| B. | Lasing more |
| C. | For producing more energetic lasers. |
| D. | All |
| Answer» B. Lasing more | |
| 24. |
The characteristic X-rays spectrum is due to |
| A. | The illumination of the target metal by ultra-violet radiation. |
| B. | The bombardment of the target by protons. |
| C. | The bombardment of target by electrons. |
| D. | The absorption of ? radiation by the target metal. |
| Answer» D. The absorption of ? radiation by the target metal. | |
| 25. |
The penetrating power of X-rays depends on their |
| A. | Applied voltage |
| B. | Frequency |
| C. | Source |
| D. | All of the above |
| Answer» C. Source | |
| 26. |
The radiations emitted form hydrogen filled discharge tube show |
| A. | Band spectrum |
| B. | Line spectrum |
| C. | Continuous spectrum |
| D. | Absorption spectrum |
| Answer» C. Continuous spectrum | |
| 27. |
The electric P.E of an electron in an orbit at a distance rn from the positive charge |
| A. | Ke2/rn |
| B. | Ke2/rn2 |
| C. | ?Ke2/rn |
| D. | ?Ke2/rn2 |
| Answer» D. ?Ke2/rn2 | |
| 28. |
The minimum wavelength of X-rays can further be reduced by |
| A. | Reducing the pressure or cooling the target. |
| B. | Increasing the temperature of the filament. |
| C. | Using a target element of higher atomic number. |
| D. | Increasing the potential difference between the cathode and the target. |
| Answer» E. | |
| 29. |
The metastable state for an atom in laser light is |
| A. | 10-4 sec |
| B. | 10-5 sec |
| C. | 10-3 sec |
| D. | 10-8 sec |
| Answer» D. 10-8 sec | |
| 30. |
The penetrating power of X-rays is comparable with that of |
| A. | ? - rays |
| B. | ? - rays |
| C. | ? - rays |
| D. | All of above |
| Answer» D. All of above | |
| 31. |
The velocity of laser light is |
| A. | Less than ordinary light. |
| B. | More than ordinary light. |
| C. | Equal to ordinary light. |
| D. | Different for different colours or frequency. |
| Answer» D. Different for different colours or frequency. | |
| 32. |
In He-Ne laser the lasing action is produced by |
| A. | Ne only. |
| B. | He-Ne both |
| C. | Electrons of He. |
| D. | Electrons Ne. |
| Answer» B. He-Ne both | |
| 33. |
In hydrogen spectrum which one of the following series lies in the ultraviolet region? |
| A. | Balmer series |
| B. | Pfund series |
| C. | Bracket series |
| D. | Lymann series |
| Answer» E. | |
| 34. |
In laser production the state in which more atoms are in the upper state than in the lower one is called |
| A. | Metal stable state. |
| B. | Normal state. |
| C. | Inverted population. |
| D. | All the above. |
| Answer» D. All the above. | |
| 35. |
In normal state of energy the incident high energy photons will be |
| A. | Stimulated. |
| B. | Absorbed. |
| C. | Cause X-ray emission. |
| D. | Cause laser production. |
| Answer» C. Cause X-ray emission. | |
| 36. |
Maximum frequency in the spectrum from X-ray tube is directly proportional to the |
| A. | Number of incident electron i.e. filament current. |
| B. | The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated. |
| C. | The soft target which can easily emit electrons. |
| D. | All of above are correct. |
| Answer» C. The soft target which can easily emit electrons. | |
| 37. |
In obtaining an X-ray photograph of our hand we use the principle of |
| A. | Photo electric effect |
| B. | Ionization |
| C. | Shadow photograph |
| D. | Any of above |
| Answer» D. Any of above | |
| 38. |
Photon of highest frequency will be absorbed when transition takes place from |
| A. | 1st to 5th orbit |
| B. | 2nd to 5th orbit |
| C. | 3rd to 5th orbit |
| D. | 4th to 5th orbit |
| Answer» B. 2nd to 5th orbit | |
| 39. |
Quality of X-rays depends upon ___________ A-filament current B-accelerating voltage C-material of the target |
| A. | A&B |
| B. | B&C |
| C. | A&C |
| D. | A B & C |
| Answer» C. A&C | |