Tiêu đề Unit No. 9 Electronics + Modern Physics (S.C) Google Drive Link By Sir Shahid.pdf ✅

ELECTRONICS + MODERN PHYSICS (UNIT-9) MDCAT www.youtube.com/physicswithshahid Q1. The semi-conductor diode has the property of: a) One way conduction b) Two way conduction c) Zero conduction d) Zone of these Q2. The number of diodes used in bridge rectifier is (a) one (b) two (c) three (d) four Q3. A pn junction (D) shown in the figure can act as a rectifier. An alternating current source (V) is connected in the circuit. The output current in the circuit is represented by: A) B) C) D) Q4. In half wave rectifier, the output voltage is taken across A) Diode C) Resistor B) Both A and C D) Any of A or C Q5. For single phase supply frequency of 50 Hz, ripple frequency in full wave rectifier is A) 25 Hz B) 50 Hz C) 100 Hz D) 200 Hz Q6. In an half wave rectifier, the input sine wave is 250sin100 t. The output ripple frequency of rectifier will be A) 100Hz B) 200Hz C) 50Hz D) 25Hz Q7. Rectifier allows unidirectional current through load during entire 360° of input cycle is A) halfwave rectifier B) full wave rectifier C) comparator D) amplifier Q8. Which one is reverse-biased? A) B) C) D)
ELECTRONICS + MODERN PHYSICS (UNIT-9) MDCAT www.youtube.com/physicswithshahid Q9. AC voltage is fed into a single diode rectifier. The output of the rectifier is A) Full wave rectified dc voltage C) Double frequency AC voltage B) Half wave rectified dc voltage D) None of these Q10. A particle which has zero rest mass and non-zero energy and momentum must travel with a speed A) Equal to c, the speed of light in vacuum C) Less than c B) Greater than c D) Tending to infinity Q11. Frequency of photon having energy 66 eV is A) 8×10−15Hz B) 12×10 −15Hz C) 16×10 15Hz D) None of these Q12. If the energy of the photon is increased by a factor of 4, then its momentum A) Does not change C) Increases by a factor of 4 B) Decreases by a factor of 4 D) Decreases by a factor of 2 Q13. Which one of the series of hydrogen spectrum is in the visible region? A) Lyman series B) Balmer series C) Paschen series D) Bracket series Q14. The energy levels of the hydrogen spectrum is shown in figure. There are some transitions A, B, C, D and E. Transition A, B and C respectively represent A) First member of Lyman series, third spectral line of Balmer series and the second spectral line of Paschen series B) Ionization potential of hydrogen, second spectral line of Balmer series and third spectral line of Paschen series C) Series limit of Lyman series, third spectral line of Balmer series and second spectral line of Paschen series D) Series limit of Lyman series, second spectral line of Balmer series and third spectral line of Paschen series Q15. Number of spectral lines in hydrogen atom is A) 3 B) 6 C) 15 D) Infinite Q16. In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change? A) From n = 2 to n = 1 C) From n = 4 to n = 2 B) From n = 3 to n = 1 D) From n = 3 to n = 2 Q17. According to Bohr's theory the moment of momentum of an electron revolving in second orbit of hydrogen atom will be A) 2πh B) πh C) h/π D) 2h/π
ELECTRONICS + MODERN PHYSICS (UNIT-9) MDCAT www.youtube.com/physicswithshahid Q18. In Bohr's model of hydrogen atom, let PE represents potential energy and TE the total energy. In going to a higher level A) PE decreases, TE increases C) PE decreases, TE decreases B) PE increases, TE increases D) PE increases, TE decreases Q19. With increasing quantum number, energy difference between adjacent levelsin atoms A) decreases B) increases C) remain constant D) zero Q20. Wavelength of a 1 keV photon is 1.24×10 −9m. What is the frequency of 1 MeV photon? A) 1.24×1015Hz B) 2.4×10 20Hz C) 1.24×10 18Hz D) 2.4×10 23Hz Q21. The frequency of a photon, having energy 100 eV is (h=6.610 −34J-sec) A) 2.42×1026Hz B) 2.42×10 16Hz C) 2.42×10 12Hz D) 2.42×10 9Hz Q22. Energy of photon whose frequency is 1012MHz, will be A) 4.14×103 keV B) 4.14×10 2eV C) 4.14×10 3MeV D) 4.14×10 3eV Q23. The momentum of photon is A) h c B) h λ C) hc λ D) Both B and C Q24. The direction of current through the resistor in the circuit shown during negative half of A.C. will be (A) From A to B (B) From B to A (C) No current flows during negative half (D) both a and B are possible Q25. Brackett series is obtained when electronic, transitions terminate on the (A) 1 st orbit (B) 3 rd orbit (C) 2 nd orbit (D) 4 th orbit Q26. Balmer series is of the historical importance as it (A) Lies in the infra-red region (B) Lies in the far-ultraviolet region (C) Lies in the visible region (D) Lies in the far-infra red region Q27. The experimental value of Rydberg’s constant is (A) 1.097 x 10 – 8m – 1 (B) 1.097 x 107m – 1 (C) 1.097 x 108 m – 1 (D) 109.7 x 10 - 8 m – 1 Q28. The given diagram indicates the energy levels of a certain atom. When the system moves from 2E to E, the wavelength of photon emitted is . The wavelength of photon emitted when transition takes place from 4E 3 level to E is : (A) λ 3 (B) 4λ 3 (C) 3λ 4 (D) 3
ELECTRONICS + MODERN PHYSICS (UNIT-9) MDCAT www.youtube.com/physicswithshahid Q29. The frequency of a photon, having energy 100 eV is (h = 6.610–34 J-sec) (A) 2.42 × 1026 Hz (B) 2.42 × 1016 Hz (C) 2.42 × 1012 Hz (D) 2.42 × 109 Hz Q30. The value of the wavelength of radiation emitted due to transition of electrons from n=4 to n=2 state in hydrogen atom will be (A) H 5R 36 (B) H 16 3R (C) H 36 5R (D) H 3R 16