Title QM DPP Sheet 01.pdf ✅

3 North Delhi : 56-58, First Floor, Mall Road, G.T.B. Nagar (Near Metro Gate No. 3), Delhi-09, Ph: 011-41420035 South Delhi : 28-A/11, Jia Sarai, Near-IIT Metro Station, New Delhi-16, Ph : 011-26851008, 26861009 16. The variation of photocurrent vs collector plate potential for three different intensities I 1 , I 2 and I 3 having frequencies v1 , v2 and v3 , respectively incident on a photosensitive surface. Then Photoelectic current I1 I2 I3 Collector plate potential (a) v2 = v3 (b) v1 = v2 (c) v1 = v3 (d) v1 < v2 17. A point source of light is used in a photoeletric effect. If the source is removed farther from the emitting metal, the stopping potential (a) will increase (b) will decrease (c) will remain constant (d) will either increase or decrease 18. The vaiation of photoelectric current I versus applied voltage (V) for two different photosensitive materials and for two different intesities of the incident radiations. Which among the following pairs of curves corresponds to different materials but same intensity of incident radiation ? I 3 1 2 4 v \ (a) (1 & 2) and (3&4) (b) (1 & 3) and (2&4) (c) (1 & 4) and (2&3) (d) None of these PART - B: Numerical Answer Type (NAT) Questions 19. The energy of a photon coming out of sodium vapour lamp ( 0   5890A ) is ___________________ eV. [Your answer should be upto TWO DECIMAL PLACES] 20. In an experiment, tungsten cathode having a threshold wavelength 2300A0 is irradiated by a light of wavelength 1800 A0 . The maximum energy of the emitted photo electrons is ___________________ eV. [Your answer should be upto TWO DECIMAL PLACES] 21. The magnitude of linear momentum of a photon in a beam of He-Ne Laser (6340A0 ) is _______________ eV/c. [Your answer should be upto TWO DECIMAL PLACES] 22. The photon energy for light of wavelength 700 nm is approximately equal to ____________________ eV. [Your answer should be upto TWO DECIMAL PLACES]
4 North Delhi : 56-58, First Floor, Mall Road, G.T.B. Nagar (Near Metro Gate No. 3), Delhi-09, Ph: 011-41420035 South Delhi : 28-A/11, Jia Sarai, Near-IIT Metro Station, New Delhi-16, Ph : 011-26851008, 26861009 23. A 1 kW radio transmitter operates at a frequency of 880 kHz. The number of photons emitted per second by it is _______________________ 30 10 . [Your answer should be upto TWO DECIMAL PLACES] 24. A detached retina is being “welded” back in place using 20 ms pulses from a 0.50 W laser operating at a wavelength of 632 nm. The number of photons in pulse is ________________________ 16 10 . [Your answer should be upto TWO DECIMAL PLACES] 25. A parallel beam of monochromatic light of wavelength 500 nm is incident normally on perfectly absorbing surface. The power through any cross-section of beam is 10 W. The magnitude of force exerted by light beam on the surface is _________________ 8 10 N   . [Your answer should be upto TWO DECIMAL PLACES] 26. A monochromatic source of light operating at 200 W emits 4×1020 photons per second. The wavelength of the light is ______________________ nm. [Your answer should be AN INTEGER] 27. The work function of copper is 4.5 eV. The threshold wavelength for photoelectric effect from a copper surface is _________________________ nm. [Your answer should be AN INTEGER] 28. The maximum wavelength for photoelectric emission in tungsten is 230 nm. The wavelength of light that must be used in order for electrons with a maximum energy of 1.5 eV to be ejected __________________ nm. [Your answer should be AN INTEGER] 29. 1.5 mW of 400 nm light is directed at a photoelectric cell. If 0.10 percent of the incident photons produce photoelectrons, then the current in the cell will be __________________________  A . [Your answer should be upto TWO DECIMAL PLACES] 30. Light of wavelength 400 nm is shone on a metal surface with work function 2.50 eV. The speed of the fastest photoelectrons is ______________ 5 10 / s m . [Your answer should be upto ONE DECIMAL PLACES] 31. Two sources P and Q produce electromagnetic waves with wavelength  and 2 respectively. Source P ejects a photon with a maximum kinetic energy of 4.0 eV from a metal with work function 2.0 eV. The maximum kinetic energy (in eV) of a photon ejected by source Q from the same metal is ________________________ eV. [Your answer should be AN INTEGER] 32. The electric field associated with a monochromatic beam becomes zero 15 1.2 10  times per second. When this light falls on a metal surface (having work function 2 eV), the maximum kinetic energy of the emitted photoelectrons will be ________________________ eV. [Your answer should be upto TWO DECIMAL PLACES] 33. The elcetric field associated with a light wave, is given by    7 1 0 E E m x ct sin 1.57 10         . When this light is used in an experiment on photoelectric effect with the emitter having work function 1.9 eV, the stopping potential will be ____________________________ V. [Your answer should be upto ONE DECIMAL PLACES]