[{"id":253994,"question":"Ultraviolet radiation of 6.2 eV falls on an aluminium surface having work function β
= π. π ππ½.
The kinetic energy of the fastest electron emitted is:
","choices":[{"text":"4 eV","value":"A"},{"text":"2 eV","value":"B"},{"text":"2.2 eV","value":"C"},{"text":"1.2 eV","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253993,"question":"The threshold frequency depends on the nature on:","choices":[{"text":"Natural frequency","value":"A"},{"text":"Photosensitive anode","value":"B"},{"text":"Photosensitive cathode","value":"C"},{"text":"Photon","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253990,"question":"The frequency and work function of an incident photon are n andππ. If f0 is the threshold frequency, then necessary condition for the emission of photo electron is:","choices":[{"text":"< π0","value":"A"},{"text":"π β₯ π0","value":"B"},{"text":"f = π0/2","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253987,"question":"The momentum of the moving photon is:","choices":[{"text":"Zero","value":"A"},{"text":"β","value":"B"},{"text":"π","value":"C"},{"text":"βπ","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253971,"question":"An electron and a proton are accelerated through the same potential. If their masses are me and mp respectively, then the ratio of their de-Broglie wavelength is:","choices":[{"text":"1","value":"A"},{"text":"mp/me","value":"B"},{"text":"me/mp","value":"C"},{"text":"","img":"253971_638248540205804524-RA4.png","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253961,"question":"Light elements do not emit X-rays because","choices":[{"text":"Electrons in it have high binding energy","value":"A"},{"text":"These materials are non- material","value":"B"},{"text":"There is a small difference in their energy shells","value":"C"},{"text":"Electrons in it require very large energy to remove from these materials","value":"D"},{"value":"E"}],"correctAnswer":3},{"id":253960,"question":"Of electron of 50 keV strike a heavy target. Then radiation emitted by target will be","choices":[{"text":"Visible light","value":"A"},{"text":"Radio waves","value":"B"},{"text":"Ultraviolet","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253959,"question":"Continuous spectrum of X-rays id due to an effect known as","choices":[{"text":"Photoelectric effect","value":"A"},{"text":"Compton effect","value":"B"},{"text":"Heisenberg effect","value":"C"},{"text":"Bremsstrahlung","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253958,"question":"Which of the following statement is true about soft X-rays?","choices":[{"text":"They have large wavelength","value":"A"},{"text":"They have high energy","value":"B"},{"text":"They have low energy","value":"C"},{"text":"Both A and C","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253957,"question":"Light of frequency 1.5 times the threshold frequency is incident on a photo sensitive material. If the frequency is halved and intensity is doubled the photo electric current becomes","choices":[{"text":"Four times","value":"A"},{"text":"Half","value":"B"},{"text":"Double","value":"C"},{"text":"Zero","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253955,"question":"The maximum energy of the electrons released in a photo cell is independent of:","choices":[{"text":"Frequency of incident light","value":"A"},{"text":"Intensity of incident light","value":"B"},{"text":"Nature of cathode rays","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253954,"question":"The minimum energy required to remove an electron is called:","choices":[{"text":"Stopping potential","value":"A"},{"text":"Work function","value":"B"},{"text":"Kinetic energy","value":"C"},{"text":"None of these","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253953,"question":"electrons from the surface of a metal when:","choices":[{"text":"It is heated to a high temperature","value":"A"},{"text":"Radiation of suitable wavelength falls on it","value":"B"},{"text":"Electrons of suitable velocity strike it","value":"C"},{"text":"It is placed in a strong electric field","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253951,"question":"Which of the following is not true?","choices":[{"text":"The Lyman series is a continuous spectrum","value":"A"},{"text":"The Ballmer series is a line spectrum in the visible region","value":"B"},{"text":"The Paschen series is a line spectrum in the infrared region","value":"C"},{"text":"The spectral series formula can be derived from Rutherfordβs model of the hydrogen atom 18. The photoelectric effect is the ejection of","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253949,"question":"An electron in the n=1 orbit hydrogen atom is bound by 13.6 eV. If a hydrogen atom is in the n=3 state, how much energy is required to ionize it:","choices":[{"text":"13.6 eV","value":"A"},{"text":"4.53 eV","value":"B"},{"text":"3.4 eV","value":"C"},{"text":"1.51eV","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253948,"question":"The potential difference applied to an X-rays tube is increased. As a result, in the emitted radiation","choices":[{"text":"The intensity increases","value":"A"},{"text":"The minimum wavelength decrease","value":"B"},{"text":"The intensity remains unchanged","value":"C"},{"text":"Both B & C","value":"D"},{"value":"E"}],"correctAnswer":4},{"id":253947,"question":"Light of frequency 4f0 is incident on the metal of the threshold frequency f0. The maximum kinetic energy of the emitted photoelectrons is","choices":[{"text":"3h f0","value":"A"},{"text":"3/2h f0","value":"B"},{"text":"2h f0","value":"C"},{"text":"1/2h f0","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253946,"question":"Figure represents a graph of kinetic energy (K) of the photoelectrons (in eV) and frequency (v) for a metal used as cathode in photoelectric experiment. The work function of metal is:","choices":[{"text":"1 eV","value":"A"},{"text":"2 eV","value":"B"},{"text":"1.5 eV","value":"C"},{"text":"3 eV","value":"D"},{"value":"E"}],"correctAnswer":2},{"id":253945,"question":"The ratio of the longest and shortest wavelength of the Lyman series is approximately:","choices":[{"text":"4/3","value":"A"},{"text":"9/4","value":"B"},{"text":"9/5","value":"C"},{"text":"16/7","value":"D"},{"value":"E"}],"correctAnswer":1},{"id":253944,"question":"According to Bohrβs theory, a line in the Ballmer series arises when the electron jumps from any of the higher orbits to the orbit with quantum number:","choices":[{"text":"1","value":"A"},{"text":"2","value":"B"},{"text":"3","value":"C"},{"text":"4","value":"D"},{"value":"E"}],"correctAnswer":2}]