MDCAT Physics MCQ's Test With Answers

MDCAT Physics MCQ's Test

Sr. # Questions Answers Choice
1 A thorium nucleus is formed when a uranium nucleus emits an π‘Ž βˆ’particles. Atomic number of thorium is : 23 60 90 70
2 When an electron in an atom goes from a lower to higher its: K.E. increases, P.E. decreases K.E. increases P.E increases K.E. decrease, P.E. increases
3 When a radioactive nucleus emits a 𝖰 βˆ’paritcles, the mass number of the atom: Increases by one Decreases by one Remains the same Decreases by four
4 The shortest wavelength of X-rays emitted from an X-rays tube depends on the: Current in the tube Voltage applied to the tube Nature of gas in the tube Nature of material of tube
5 In an π‘Ž βˆ’decay: The parent and daughter nuclei have same number of protons The daughter nucleus has one proton more than parent nucleus The daughter nucleus has two protons less than parent nucleus The daughter nucleus has two neutrons more than parent nucleus
6 For X-rays which of the following is not correct: Cause of ionization in air when they pass through it Can be deflected by electric and magnetic fields Can be used to detect flaws in metal casting Travel with the speed of light
7 Half-life of radon gas is: 1620 years 3.8 days 7 days 11 days
8
Ultraviolet radiation of 6.2 eV falls on an aluminium surface having work function βˆ… = πŸ’. 𝟐 𝒆𝑽.
The kinetic energy of the fastest electron emitted is:
 4 eV 2 eV 2.2 eV 1.2 eV
9 The threshold frequency depends on the nature on: Natural frequency Photosensitive anode Photosensitive cathode Photon
10 Nuclear fission experiments show that the neutrons the uranium nuclei into two fragment of about the same size. This process is accompanied by the emission of several: Protons and positrons 𝛼 −partilces neutrons Protons and 𝛼 −partilces
11 The frequency and work function of an incident photon are n andπ‹πŸŽ. If f0 is the threshold frequency, then necessary condition for the emission of photo electron is: < 𝑓0 𝑓 ≥ 𝑓0 f = 𝑓0/2 None of these
12 The example of nuclear fusion is: Formation of barium and krypton from uranium Formation of plutonium -235 from uranium -235 Formation of helium from hydrogen Formation of water from hydrogen and oxygen
13 The momentum of the moving photon is: Zero ℎ 𝜆 ℎ𝜆
14 π‘Ž, 𝖰 𝒂𝒏𝒅 radiations come out of radioactive substance: Spontaneously When it is put in a reactor When it is heated Under pressure
15 A radioactive substance has a half-life of 4 months. Three-fourths of the substance will decay in: 5months 6months 8months 7months
16 For atomic nucleus, the binding energy per nucleon with increase in mass number: Increases continuously Remains same Decrease continuously First increases and then decreases with increase in mass number
17 A count rate 240 per minute reduces to 30 counts per min in 1 hour. The half-life of source is: 20min 60min 80min 90min
18 The phenomenon of radioactivity is associated with: Fission of nucleus Disintegration of neutrons Emission of spectral lines Spontaneous disintegration of the nuclei of atoms
19 The mother and daughter elements with the emission of 𝖰 βˆ’ π’“π’‚π’šπ’”, are called: Isotopes Isobars Isomers Isodiapheres
20 The activity of a radioactive sample is 1.6 curie and half-life is 2.5 days. Its activity after 10 days will be: 0.8 Curie 0.1Curie 0.4 Curie 0.16 Curie
21 In 420 days, the activity of a sample of polonium (Po) fell to one-eight of its initial value. The half-life of polonium is : 140days 45days 87days 90days
22 A radioactive isotope πŸπŸ‘πŸ– 𝑼 decays consecutively to πŸπŸ‘πŸ’ 𝑼 the particles emitted are: One 𝛼 and one 𝛽 Two 𝛼 and one 𝛽 e 𝛼 and two 𝛽 Two 𝛼 and two 𝛽
23 An electron and a proton are accelerated through the same potential. If their masses are me and mp respectively, then the ratio of their de-Broglie wavelength is: 1 mp/me me/mp
24 The uranium Nucleus πŸπŸ‘πŸ– 𝑼 undergoes successive decays, emitting respectively π‘Ž βˆ’ π’“π’‚π’š,𝖰 βˆ’ π’“π’‚π’š 𝒂𝒏𝒅 βˆ’ π’“π’‚π’šπ’”. What is the atomic number and atomic mass of the resulting nucleus: 90, 238 91, 234 92, 236 92, 238
25 A radioactive nucleus can emit: Electron 𝛼 particles Positron Any of these
26 Which of the following have maximum ionization power? 𝛼 −rays 𝛽 −rays 𝛾 −rays Same for all
27 Due to emission of 𝖰+ βˆ’ π’“π’‚π’šπ’”: Mass of the nucleus increases Mass of the nucleus decreases Charge on the nucleus increases Charge number decreases
28 Light elements do not emit X-rays because Electrons in it have high binding energy These materials are non- material There is a small difference in their energy shells Electrons in it require very large energy to remove from these materials
29 Of electron of 50 keV strike a heavy target. Then radiation emitted by target will be Visible light Radio waves Ultraviolet None of these
30 Continuous spectrum of X-rays id due to an effect known as Photoelectric effect Compton effect Heisenberg effect Bremsstrahlung
31 Which of the following statement is true about soft X-rays? They have large wavelength They have high energy They have low energy Both A and C
32 Light of frequency 1.5 times the threshold frequency is incident on a photo sensitive material. If the frequency is halved and intensity is doubled the photo electric current becomes Four times Half Double Zero
33 The half-life of a radioactive element which has only 1//32 of its original mass left after a lapse of 60 days is: 12days 10days 22days 36days
34 The maximum energy of the electrons released in a photo cell is independent of: Frequency of incident light Intensity of incident light Nature of cathode rays None of these
35 The minimum energy required to remove an electron is called: Stopping potential Work function Kinetic energy None of these
36 electrons from the surface of a metal when: It is heated to a high temperature Radiation of suitable wavelength falls on it Electrons of suitable velocity strike it It is placed in a strong electric field
37 The half-life of a certain element is 3.5 days at STP. If the temperature is doubled and pressure is reduced to half then half-life of the same element will be: 1.75 days 3.5 days 7 days 14 days
38 Which of the following is not true? The Lyman series is a continuous spectrum The Ballmer series is a line spectrum in the visible region The Paschen series is a line spectrum in the infrared region The spectral series formula can be derived from Rutherford’s model of the hydrogen atom 18. The photoelectric effect is the ejection of
39 If the radioactive substance reduces to 𝟏 πŸπŸ” PHYSICS of its original mass in 40 days then its half-life is: 10days 20days 40days 4days
40 An electron in the n=1 orbit hydrogen atom is bound by 13.6 eV. If a hydrogen atom is in the n=3 state, how much energy is required to ionize it: 13.6 eV 4.53 eV 3.4 eV 1.51eV
Download This Set

Is this page helpful?