PPSC Physics Topic 7 Modern Physics With Answers

PPSC Physics Topic 7 Modern Physics

Sr. # Questions Answers Choice
1 In the Geiger Marsden experiment a narrow beam of alpha particles was fired at a thin piece of Gold foil in a vacuum Some of the particles were scattered though large angles The result of the experiment provided evidence for the existence of. A very small charged nucleus electrons orbiting the nucleus Neutrons in the nucleus Nuclear reaction
2 Which particle interact via all fundamental forces. Leptons Hadrons Muons mesons
3 Which of the following are particle accelerators. Cyclotrons Synchrotrons Linear accelerators All of the above
4 The best shield against Gama rays would be of Heavy water Aluminium Iron Lead
5 The working of cloud chamber is based in the presence of. Super heated vapours Liquid Super saturated vapors Unsaturated vapours
6 The path of Gama rays in Wilson cloud chamber is Irregular Dense and straight Thin and continuous Thin and discontinuous
7 What are isotopes. Atoms of the same element with different numbers of neutrons. Atoms of the same element with different numbers of protons. Atoms which are radioactive Atoms which have gained or lost an electron
8 The neutral atoms of all isotopes of the same element contain the same numbers of. Electrons and protons Electrons and neutrons Neutrons Neutrons and protons
9 The back ground radiation in the atmosphere on the average is 0.5 Sv per year 1.0 Sv per year 1.5 Sv per year 2.0 Sv per year
10 In a cloud chamber the Alpha particles leave Dense, straight and continuous tracks Only straight and continuous tracks Thin and discontinuous tracks Irregular tracks
11 Which particle has zero charge and zero rest mass. Neutron Proton Electron Photon
12 In which reaction two or more small light nuclei nuclei come together or fuse to form a large nucleus. Radioactivity Radioactivity dating Nuclear fusion Nuclear fission
13 In a Nuclear reactor which material is often used as modeerator. Water Graphite Uranium Water and graphite
14 In which of the following controlled nuclear chain reaction is used to liberate energy. Nuclear bomb Atomic bomb Hydrogen bomb Nuclear reactor
15 Induced fission result from the absorption of electron Proton Nucleon Neutron
16 Ashes from a campfire deep in a cave show carbon -14 activity of only one eighth the activity of fresh wood. How long ago was that campfire made. 13590 years 15190 years 17190 years 21190 years
17 Half life of a radioactive elements 10 minutes If the initial cont. rate is 368 counts per minute for what time count rate reaches 32 counts per minute. 20 minutes 40 minutes 80 minutes 120 minutes
18 Cobalt -60 is a radioactive element with half life of 5.25 years. What fraction of the original sample will be left after 26 years. 1/4 1/8 1/16 1/32
19 The decay process in which an unstable nucleus splits into two fragments of comparable mass is known as. Nuclear fission nuclear fusion Radioactivity Carbon dating
20 Which of the following has the highest relative biological effectiveness or the quality factor. X rays and Gama rays Electrons Photons Alpha particles
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