MCQOPTIONS
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MCQOPTIONS
This section includes 35 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Laser Light is different from others because |
| A. | It is Coherent |
| B. | It is incoherent |
| C. | High Intensity |
| D. | High Speed |
| Answer» B. It is incoherent | |
| 2. |
If the empirical formula for the observed wavelengths (λ)for hydrogen is 1/λ = R(1/22 - 1/n2), where 'n' is integral values higher than 2, then it represents the _____________ spectral series. |
| A. | Lyman |
| B. | Balmer |
| C. | Paschen |
| D. | Brackett |
| Answer» C. Paschen | |
| 3. |
If the energy of the electron in the 1st orbit of hydrogen is -13.6 eV, then how much is the energy (in eV) in the 2nd orbit? |
| A. | -6.8 |
| B. | -27.2 |
| C. | -4.5 |
| D. | -3.4 |
| Answer» E. | |
| 4. |
Calculate the wavelength (in nm) of the spectral line of Lyman series for n = 2. (Rydberg constant = 1.1 x 107 m-1) |
| A. | 121 |
| B. | 221 |
| C. | 321 |
| D. | 421 |
| Answer» B. 221 | |
| 5. |
Louis de Broglie argued that the electron in its circular orbit must be seen as a particle wave, whose wavelength is equal to _______ , where 'p' is the magnitude of the electron’s momentum and 'h' is Planck's constant. |
| A. | hp |
| B. | p/h |
| C. | hp2 |
| D. | h/p |
| Answer» E. | |
| 6. |
In Rutherford's gold foil experiment which of the following were directed towards the gold foil? |
| A. | β-particles |
| B. | γ -particles |
| C. | electrons |
| D. | α-particles |
| Answer» E. | |
| 7. |
In whose theory the first postulate states that an electron in an atom could revolve in certain stable orbits without the emission of radiant energy? |
| A. | Planck’s |
| B. | Rydberg's |
| C. | Thomson’s |
| D. | Bohr's |
| Answer» E. | |
| 8. |
Calculate the wavelength (in nm) of the spectral line of Lyman series for n = 3. (Rydberg constant = 1.1 × 107 m-1) |
| A. | 202 |
| B. | 302 |
| C. | 102 |
| D. | 402 |
| Answer» D. 402 | |
| 9. |
Laser is produced by |
| A. | graphite |
| B. | ruby |
| C. | diamond |
| D. | emerald |
| Answer» C. diamond | |
| 10. |
If the empirical formula for the observed wavelengths for hydrogen is 1/λ = R(1/12 - 1/n2), where n is integral values higher than 1, then it represents the _____________ spectral series. |
| A. | Balmer |
| B. | Paschen |
| C. | Lyman |
| D. | Brackett |
| Answer» D. Brackett | |
| 11. |
A proton is moving at a speed of 5.0 × 104 m/s. The de Broglie wavelength associated with it is _____.(mp = 1.67 × 10-27 kg, h = 6.63 × 10-34 J s) |
| A. | 0.38 × 10-11 m |
| B. | 0.79 × 10-11 m |
| C. | 1.20 × 10-11 m |
| D. | 1.58 × 10-11 m |
| Answer» C. 1.20 × 10-11 m | |
| 12. |
Calculate the wavelength (in nm) of the spectral line of Lyman series for n = 4. (Rydberg constant = 1.1 × 107 m-1 |
| A. | 196 |
| B. | 96 |
| C. | 296 |
| D. | 396 |
| Answer» C. 296 | |
| 13. |
If the empirical formula for the observed wavelengths (λ) for hydrogen is 1 / λ = R(1 / 32 - 1 / n2), where 'n' is integral values higher than 3, then it represents the _____________ series. |
| A. | Balmer |
| B. | Lyman |
| C. | Brackett |
| D. | Paschen |
| Answer» E. | |
| 14. |
If the potential difference applied to an X-ray tube is doubled while keeping the separation between the filaments and the target as same, what will happen to the cutoff wavelength? |
| A. | Will remains same |
| B. | Will be doubled |
| C. | Will be halved |
| D. | Will be four times of the original wavelength |
| Answer» D. Will be four times of the original wavelength | |
| 15. |
In order to investigate the internal atomic structure of crystals, we make use of: |
| A. | Orange light |
| B. | X - rays |
| C. | Ultraviolet radiaion |
| D. | Infrared radiation |
| Answer» C. Ultraviolet radiaion | |
| 16. |
An electron in a TV tube has a speed of 6 × 107 m/s. What is the de Broglie wavelength associated with the electron (m = 9.11 × 10-31 kg)? |
| A. | 0.248 Å |
| B. | 0.121 Å |
| C. | 0.347 Å |
| D. | 0.867 Å |
| Answer» C. 0.347 Å | |
| 17. |
Match the type of wave with its Method of detection.A. X-rays1. Point contact diodesB. Infra-red2. ThermopilesC. Microwave3. Geiger tubes |
| A. | A - 2, B - 3, C - 1 |
| B. | A - 3, B - 2, C - 1 |
| C. | A - 2, B - 1, C - 3 |
| D. | A - 3, B - 1, C - 2 |
| Answer» C. A - 2, B - 1, C - 3 | |
| 18. |
If the empirical formula for the observed wavelengths (λ)for hydrogen is 1/λ = R(1/42 - 1/n2), where 'n' is integral values higher than 4, then it represents the _____________ series. |
| A. | Balmer |
| B. | Brackett |
| C. | Paschen |
| D. | Lyman |
| Answer» C. Paschen | |
| 19. |
In Rutherford experiment, alpha particles were made to fall in thin |
| A. | Gold foil |
| B. | Aluminium foil |
| C. | Silver plate |
| D. | Silver flask |
| Answer» B. Aluminium foil | |
| 20. |
If there are 'N' atoms in a source, each emitting light with intensity 'I', then the total intensity produced by an ordinary source is proportional to 'NI', whereas in a laser source, it is proportional to ________. |
| A. | (NI)2 |
| B. | 2NI |
| C. | NI2 |
| D. | N2I |
| Answer» E. | |
| 21. |
A proton and an alpha particle are accelerated in a field of the same potential difference. Then, the ratio of the Broglie wavelengths associated with the moving material particles is: |
| A. | 2√2 : 1 |
| B. | 1 : 2 |
| C. | 4 : 1 |
| D. | 2 : 1 |
| Answer» B. 1 : 2 | |
| 22. |
Laser light is intense because |
| A. | it has very less number of Photons that in phase |
| B. | it has very less number of Photons that are not in phase |
| C. | it has very large number of Photons that are in phase |
| D. | it has very large number of Photons that are not in phase |
| Answer» D. it has very large number of Photons that are not in phase | |
| 23. |
In Rutherford's alpha particle scattering experiment, only about _________ % of the incident α-particles scatter by more than 1°. |
| A. | 0.14 |
| B. | 1.4 |
| C. | 8.4 |
| D. | 7 |
| Answer» B. 1.4 | |
| 24. |
An electron and a proton have the same kinetic energy. Then, the ratio of de Broglie wavelengths of proton and electron will be nearly: |
| A. | 1 : 43 |
| B. | 1 : 1838 |
| C. | 1838 : 1 |
| D. | 43 : 1 |
| Answer» B. 1 : 1838 | |
| 25. |
Laser is a device for |
| A. | production of beam of white light |
| B. | producing a beam of monochromatic light |
| C. | producing a beam of high intensity rays |
| D. | producing a beam of highly penetrating x-rays |
| Answer» D. producing a beam of highly penetrating x-rays | |
| 26. |
In order to study internal atomic structure of crystals, we make use of electromagnetic radiations as _________. |
| A. | ultraviolet radiation |
| B. | red light |
| C. | yellow visible light |
| D. | x-rays |
| Answer» E. | |
| 27. |
Energy of an electron in the nth orbit of an hydrogen atom is equal to __________ eV. |
| A. | -13.6/n |
| B. | -13.6/n2 |
| C. | -13.6n2 |
| D. | -13.6n |
| Answer» C. -13.6n2 | |
| 28. |
Commonly used Laser in MB-Computer printers is ________ |
| A. | He-Ne Gas |
| B. | Ruby |
| C. | Semiconductor |
| D. | All of these |
| Answer» B. Ruby | |
| 29. |
After completing the gold foil experiment, Rutherford concluded that the size of the nucleus is very small compared to the size of the atom. This is because: |
| A. | One out of every 12000 alpha particles deflected back after hitting the gold foil |
| B. | Most of the alpha particles deflected back after hitting the gold foil |
| C. | Some alpha particles were deflected by small angles |
| D. | Very few of the alpha particles passed through the gold foil |
| Answer» B. Most of the alpha particles deflected back after hitting the gold foil | |
| 30. |
In the formula, 1/λ = R(1/52 - 1/n2) which represents the Pfund spectral series for hydrogen, 'R' is _____________ constant |
| A. | Planck |
| B. | Bohr |
| C. | Thomson |
| D. | Rydberg |
| Answer» E. | |
| 31. |
A proton (m = 1.67 × 10-27 kg) is moving at a speed of 6.0 × 105 m/s. What is its de Broglie wavelength? |
| A. | 6.62 × 10-13 m |
| B. | 2.28 × 10-13 m |
| C. | 8.93 × 10-13 m |
| D. | 1.14 × 10-13 m |
| Answer» B. 2.28 × 10-13 m | |
| 32. |
Bohr’s second postulate defines that an electron revolves only in those stable orbits where its angular momentum 'L' is some integral multiple of 'h/2π' where 'h' is the _________ constant. |
| A. | Planck ’s |
| B. | Rydberg's |
| C. | Bohr's |
| D. | Thomson’s |
| Answer» B. Rydberg's | |
| 33. |
A family of planes of spacing 0.2518 nm of NaCI crystal reflects a beam of X-ray in first order at an angle of 30°. The wavelength of X-rays is: |
| A. | 0.2518 nm |
| B. | 0.1259 nm |
| C. | 0.3778 nm |
| D. | 0.5036 nm |
| Answer» B. 0.1259 nm | |
| 34. |
In Rutherford's alpha-particle scattering experiment, the particles are directed towards a thin ___________ foil. |
| A. | lead |
| B. | gold |
| C. | aluminium |
| D. | silver |
| Answer» C. aluminium | |
| 35. |
Laser is based on the phenomenon of |
| A. | Spontaneous Emission |
| B. | Stimulated Emission |
| C. | Absorption |
| D. | Total internal Reflection |
| Answer» C. Absorption | |