[{"id":158909,"question":"The lasing or active medium in He-Ne laser discharge tube is:","choices":[{"text":"Nitrogen","value":"A"},{"text":"Helium","value":"B"},{"text":"Hydrogen","value":"C"},{"text":"Neon","value":"D"},{"text":"None of these","value":"E"}],"correctAnswer":4},{"id":158908,"question":"The spectrum emitted from hydrogen filled discharge tube is:","choices":[{"text":"Line spectrum","value":"A"},{"text":"Discrete spectrum","value":"B"},{"text":"And spectrum","value":"C"},{"text":"Absorption spectrum","value":"D"},{"text":"Both (A) and (B)","value":"E"}],"correctAnswer":5},{"id":158907,"question":"The He-Ne laser discharge tube is filled with:","choices":[{"text":"85% He","value":"A"},{"text":"15% He","value":"B"},{"text":"50% He","value":"C"},{"text":"60% He","value":"D"},{"text":"85% Ne","value":"E"}],"correctAnswer":1},{"id":158906,"question":"A metastable stae:","choices":[{"text":"Is an excited state","value":"A"},{"text":"Is that in which excited electron is stable","value":"B"},{"text":"Is that in which excited electron is usually unstable","value":"C"},{"text":"Means a time interval of 10<sup>-8</sup>second","value":"D"},{"text":"Both (A) and (C)","value":"E"}],"correctAnswer":5},{"id":158905,"question":"Laser is a beam of:","choices":[{"text":"Visible light","value":"A"},{"text":"Infra red light","value":"B"},{"text":"Ultra violet light","value":"C"},{"text":"Violet light only","value":"D"},{"text":"yellow light only","value":"E"}],"correctAnswer":1},{"id":158904,"question":"By CAT scans, we can detect the density difference of the order of:","choices":[{"text":"1%","value":"A"},{"text":"20%","value":"B"},{"text":"30%","value":"C"},{"text":"50%","value":"D"},{"text":"70%","value":"E"}],"correctAnswer":1},{"id":158903,"question":"The shell closer to the nucleus is called:","choices":[{"text":"N shell","value":"A"},{"text":"<div>L shell</div>","value":"B"},{"text":"K shell","value":"C"},{"text":"M shell","value":"D"},{"text":"O shell","value":"E"}],"correctAnswer":3},{"id":158902,"question":"An compared to solid matter, a crack or an air bubble allows:","choices":[{"text":"Great amount of X-rays to pass","value":"A"},{"text":"Smallast amount of X-rays to pass","value":"B"},{"text":"Very samall amount of X-rays to pass","value":"C"},{"text":"Any of these","value":"D"},{"text":"None of these","value":"E"}],"correctAnswer":1},{"id":158901,"question":"X-rays can penetrate in a solid matte through a distance of several:","choices":[{"text":"Kilo metres","value":"A"},{"text":"Metres","value":"B"},{"text":"Centimeters","value":"C"},{"text":"A few angstroms","value":"D"},{"text":"One micrometer","value":"E"}],"correctAnswer":3},{"id":158900,"question":"In case of braking radiations, when the rate of deceleration is very large, the emitted radiation corresponds to:","choices":[{"text":"Short wavelength","value":"A"},{"text":"Large wavelength","value":"B"},{"text":"Very large wavelenth","value":"C"},{"text":"Low frequency","value":"D"},{"text":"Both (B) and (C)","value":"E"}],"correctAnswer":1},{"id":158899,"question":"Braking radiation causes:","choices":[{"text":"Continuous spectrum","value":"A"},{"text":"Line Spectrum","value":"B"},{"text":"Band spectrum","value":"C"},{"text":"Discrete specturm","value":"D"},{"text":"All of these","value":"E"}],"correctAnswer":1},{"id":158898,"question":"The holes created in the L and M shells are occupied by transitions of:","choices":[{"text":"Electrons from lower states","value":"A"},{"text":"Electrons from higher state","value":"B"},{"text":"Positrons from higher states","value":"C"},{"text":"Electrons from K shell","value":"D"},{"text":"Both (A) and (B)","value":"E"}],"correctAnswer":2},{"id":158897,"question":"The transitions of electrons in the hydrogen atom result in the emission of spectral lies in the:","choices":[{"text":"Ultra red region","value":"A"},{"text":"Visible region","value":"B"},{"text":"Ultraviolet region","value":"C"},{"text":"Any of these","value":"D"},{"text":"None of these","value":"E"}],"correctAnswer":4},{"id":158896,"question":"Energy required by an electron revolving in certain orbit to jump to an excited state is called:","choices":[{"text":"Ionization energy","value":"A"},{"text":"Ionization potential","value":"B"},{"text":"Excitation energy","value":"C"},{"text":"Excitation potential","value":"D"},{"text":"None of these","value":"E"}],"correctAnswer":3},{"id":158895,"question":"An electron of the hydrogen atom in the second orbit is called its:","choices":[{"text":"Ground state","value":"A"},{"text":"Excited state","value":"B"},{"text":"Ionized state","value":"C"},{"text":"Any of these","value":"D"},{"text":"None of these","value":"E"}],"correctAnswer":2}]