PPSC Physics Topic 7 Modern Physics With Answers

PPSC Physics Topic 7 Modern Physics

Sr. # Questions Answers Choice
1 A slow neutron can cause fission in Uranium -238 Uranium-235 Hydrogen-1 Thorium -232
2 The critical mass of fissionable uranium -235 can be reduced by Adding impurities to it Heating the material surrounding it by neutron reflecting material Surrounding it by neutron absorbing material
3 When a posirtron is emitted it causes. Mass number to increase by one mass number to decrease by one Atomic number to decrease by one Atomic number to increase by one
4 Neutrino9 is a particle with Charge less property and has no spin Charge less property and has spin Charge less like electron and has spin The same property as neutron
5 Tracer techniques make use of. Neutron scattering Electron beams LASER Radioactive isotopes
6 The critical mass of a fission reaction is. The mass to start a nuclear fission reaction The minimum mass for chain reaction The size of the reactor core The size of fuel plus the size of moderator
7 Which of the following is formed by decay of a free neurton. A number of electrons Two protons A proton and an electron An alpha particle
8 Which of the following particles leave no trail in a cloud chamber. Electrons Protons Alpha particles Neutrons
9 Which of the following is not a mode of radioactive decay. Positron emission Electron capture Fusion reaction A decay
10 Which of the following can be used as an arrester in a nuclear reactor. Graphite heavy water Uranium Cadmium
11 Which of the following is believed to be carrier o nuclear forces. Lepton Meson Bason Baryon
12 In fission reaction, heavy water is used as a Coolant Moderator Heat exchanger Controller of reaction rate
13 Which of the following is the most massive particle. Deuteron Alpha particle Neutron positron
14 In a nuclear reactor chani reaction is controlled by introducing. Iron rods Cadmium rods Graphite rods Platinum rods
15 The process by which nuclei emit a ,b and gama rays in order to attain stability is called. Radioactive disintegration Radio activity B decay Radioactive transmulation
16 Sub atomic paticles whihc does not experience strong nuclear force are. hadrons Photons Leptons Nucleons
17 Sub atomic particles which experience strong nuclear force are. Leptons Hadrons Mesons Quarks
18 The particles less in mass than protons are Measons Bosons Baryons Nucleons
19 The phenomenon of radioactivity is associated with Decay of nucleus Decay of atoms Fusion of nuclei Emission of electrons
20 The particles equal in mass or greater than protons are called. Mesons Bosons Baryons Nucleons
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