ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics Online Test With Answers

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ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics Online Test

Sr. # Questions Answers Choice
1 The positron was discovered by: In cosmic radiation In 1932 By Carl Anderson All above By direc
2 A particle having mass and charge equal to that of an electron is called: Proton Positron Pion Pi-meson Both (C) and (D)
3 Photoelectric effect takes place with a photon of: Very high energy Very low energy Low energy High energy None of these
4 Compton shift refers to: Photon Meson Proton Positron Both (B) and (D)
5 The year when A.H. compton was awarded Nobel Prize is: 1923 1927 1931 1935 None of these
6 Compton derived an expression to find compton shift by applying to the process, the law of conservation of: Energy only Momentum only Mass only Charge only Both (A) and (B)
7 Compton studied the scattering of x-rays by loosely bound electrons from: NaCl crystal Graphite crystal Zirconia Copper crystal None of these
8 The threshold frequency of sodium is 6 x 106MHz. The cut-off wavelength for this metal will be 500 m 500 nm 500 km 500 cm None of these
9 The unit of work function is: Joule Electron volt That of threshold frequency Both (A) and (B) None of these
10 Photoelectrons are emitted when ultraviolet light falls on: Casium Silver Potassium Any of these None of these
11 The Nobel Prize on the explanation of photoelectric effect was awarded to: Max. Planck Maxwell Bohr Rutherford None of these
12 The idea of quantization of energy was proposed by: Einstein Max.Planck Maxwell Bohr Rutherford
13 Intensity of light determines the: Energy of each photon Number of photons Speed of photons Size of photons None of these
14 Electromagnetic -radiation means: Photons protons Electrons Mesons None of these
15 The way through which electromagnetic radiations or photons interact with matter depends upon their: Wavelength Frequency Energy Temperature All of these
16 If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is: Newton Joule Joule-Sec Joule-s<sup>-1</sup> Watt
17 Max Planck received the Nobel Prize for his discovery of energy quants in: 1718 AD 1918 AH 1818 AD 1918 AD None of these
18 The ratio of energy E to the corresponding frequency (f) of the radiation (emitted or absorbed) is called: Wien's constant Stefen's constnat Planck's constant Boltzmann's constant None of these
19 Wien's constant is measured in: Metre per kelviin Metre kelvin Kelvin per meter Joules Dynes
20 The intensity of emitted energy (with wavelength) radiated from a black body at different temperatures was initially measured by: Lummer Planck Pringsheim Both (A ) and (B) Both (A) and (C)
21 When platinum wire is heated, then at the temperature of 500 oC, it becomes: Yellow Orange red Dull red White Cherry red
22 The nature of radiations emitted by a hot body depends upon its: Metarial Temperature colour Volume Length
23 When the atomic particle are moving with velocities approaching that of light: Newton's laws become valid Relativistic effects become prominent Botha(A) and (B) are valid Neither (A)nor (B) There mass becomes zero.
24 As compared to the distance measured by an observer on Earth, the distance from Earth to a star measured by an observer in a moving spaceship would seem: Smaller Lerger Same Much larger None of these
25 the dilation of time applies to the timing processes which are: Physical Chemical Biological All of these None of these
26 Due to relative motion of observer and the frame of reference of events, time always: Dilates itself Contracts itself Stretches itself Both (A) and (C) None of these
27 Practically the quantity v/c is always: less than one Equal to one Greater then one all of these None of these
28 the symbol to be used in relativity problems denotes: Dilated time Proper time Life time Half time None of these
29 There is no way to detect: Absolute uniform motion Accelerated motion State rest State of motion None of these
30 The special theory of relativity is based on: Four postulates Three postulates Two postulates One postulate None of these
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