NAT II Physical Science Physics With Answers

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NAT II Physical Science Physics

Sr. # Questions Answers Choice
1 In which of the following states does the incandescent substance give continuous spectrum? Vapours in atomic state Vapours in molecular state Solid or fluid in bulk state Solid or fluid in plasma state
2 Which of the following sources give discrete emission spectrum? Incandescent electric bulb Sun Mercury vapour lamp Candle
3 There are discrete energy levels in atoms. It was first experimentally demonstrated by Rutherford's experiment Franck Hertz experiment Marsden's experiment Somerfield experiment
4 The essential distinction between X-rays andγ-rays is that <span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: small;">γ-rays have smaller wavelength than X-rays</span> <span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: small;">γ-rays emanate from nucleus while X-rays emanate from outer part of the atom</span> <span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: small;">γ-rays have greater ionizing power than X-rays</span> <span style="color: rgb(34, 34, 34); font-family: arial, sans-serif; font-size: small;">γ-rays are more penetrating than X-rays</span>
5 A photoelectric cell coverts Electrical energy to light energy Light energy to light energy Light energy to electrical energy Light energy to elastic energy
6 Ultra-violet radiation of 6.2 eV falls on an aluminium surface. K.E. of fastest electron emitted is (Work function = 4.2 eV) 3.2 x 10-21 J 3.2 x 10-19 J 7 x 10-25 J 9 x 10-32 J
7 When light wavelength 300 nm (nanometer) falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, however, light of 600 nm wavelength is sufficient for creating photoemission. What is the ratio of the work functions of the two emitters? 1 : 2 2 : 1 4 : 1 1 : 4
8 The frequency of the incident light falling on a photosensitive metal plate is doubled, the kinetic energy of the emitted photoelectrons is Double the earlier value Unchanged More than doubled Less than doubled
9 A monochromatic source of light is placed at a large distance d from a metal surface. Photoelectrons are ejected at rate n, kinetic energy being E. If the source is brought nearer to distance d/2, the rate and kinetic energy per photoelectron become nearly 2n and 2E 4n and 4E 4n and E N and 4E
10 A photocell with a constant p.d. of V volt across it illuminated by a point source from a distance of 25 cm. When the source is moved to a distance of 1m, the electrons emitted by the photocell Carry 1/4th their previous energy Are 1/16th as numerous as before Are 1/4th as numerous as before Carry 1/4th their previous momentum
11 Radio waves of constant amplitude can be generated with Rectifier Filter FET oscillator
12 Copper and germanium are cooled to 70K from room temperature, then Resistance of copper increases while that of germanium decreases Resistance of copper decreases while that of germanium increases Resistance of both decreases Resistance of both increases
13 When n-type of semiconductor is heated Number of electrons increases while that of holes decreases Number of holes increases while that of electron decreases Number of electrons and holes remains same Number of electrons and holes increases equally
14 The part of a transistor which is heavily doped to produce large number of majority carriers is Emitter Base Collector Any of the above depending on nature of transistor
15 A p-n junction has a thickness of the order of: 1 cm 1 mm 10<sup>-6</sup>cm 10<sup>-12</sup>cm
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