Free Discovery of the Proton MCQs with Answers
72 Discovery of the Proton MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The discovery of the proton follows the study of positive rays, also called canal rays, observed in discharge tubes and later identified as positively charged particles. The work of Goldstein and Rutherford is linked to the proton's charge, relative mass and role in the nuclear model, distinct from the discovery of the electron.
Last updated
72 questions · page 2 of 4
- A. Electron
- B. Positron
- C. Neutron
- D. None of above has such capability
Explanation: Fast neutrons can knock protons out of hydrogen-rich paraffin by elastic collisions, because paraffin contains many hydrogen nuclei and a…
Correct answer: Neutron- A. Gamma-rays
- B. Alpha-rays
- C. Beta-rays
- D. X-rays
Explanation: Rutherford used alpha particles, which are positively charged helium nuclei, in the gold-foil experiment that revealed the small, dense…
Correct answer: Alpha-rays- A. J.J Thomson
- B. Millikan
- C. Rutherford
- D. Perrin
Explanation: Millikan measured the magnitude of the electron’s charge using the oil-drop experiment by balancing electrical force against gravitational…
Correct answer: Millikan- A. Neutrino
- B. Electron
- C. Both A & B
- D. Meson
Explanation: In beta-minus decay, a free neutron changes into a proton while emitting an electron and an antineutrino: n → p + e⁻ + antineutrino.
Correct answer: Both A & B- A. Alpha emission
- B. Beta emission
- C. Both A & B
- D. Radioactivity
Explanation: In beta-minus emission, a neutron changes into a proton and an electron, so the atomic number increases by 1 while the mass number remains…
Correct answer: Beta emission26. The number of fundamental particles in an atom of the lightest isotope carbon are_______________?
- A. 6
- B. 12
- C. 18
- D. 20
Explanation: The lightest isotope of carbon is carbon-12, containing 6 protons, 6 neutrons and 6 electrons.
Correct answer: 18- A. Rutherford
- B. Dalton
- C. Bohr
- D. Schrodinger
Explanation: Dalton proposed that matter is made of tiny indivisible atoms, which was an early atomic theory.
Correct answer: Dalton- A. By burning of gas
- B. By cooling of the gas
- C. By the bombardment of cathode rays on gas molecules
- D. From anode like cathode rays produced from cathode
Explanation: Cathode rays collide with gas molecules and remove electrons from them, producing positively charged ions.
Correct answer: By the bombardment of cathode rays on gas molecules- A. Temperature
- B. Pressure
- C. Volume
- D. Composition of glass
Explanation: Cathode rays produce fluorescence when they strike the glass, and the colour depends mainly on the composition of the glass or fluorescent…
Correct answer: Composition of glass- A. Milk
- B. Honey
- C. Oil
- D. Water
Explanation: Millikan used tiny oil droplets in his oil-drop experiment to measure the electronic charge.
Correct answer: Oil- A. 6.02 x 10^23 C/kg
- B. 1.7588 x 10^20 C/kg
- C. 9.1095 x 10^-31 C/kg
- D. 1.7588 x 10^11 C/kg
Explanation: The charge-to-mass ratio of an electron is e/m = 1.602 x 10^-19 C / 9.1095 x 10^-31 kg = 1.7588 x 10^11 C/kg.
Correct answer: 1.7588 x 10^11 C/kg- A. AgNO3 plate
- B. AgCl plate
- C. ZnO
- D. ZnS
Explanation: Positive rays produce visible flashes when they strike a fluorescent material such as zinc sulfide, ZnS.
Correct answer: ZnS- A. Hitorff
- B. Stoney
- C. William Crookes
- D. J.Perrin
Explanation: J. J. Thomson studied positive rays, while J. Perrin investigated their deflection and showed that they carried positive charge.
Correct answer: J.Perrin- A. 10 torr
- B. 1 torr
- C. 0.1 torr
- D. 0.01 torr
Explanation: Gas discharge tubes used to study cathode and positive rays were maintained at very low pressure, commonly about 0.01 torr, so that the…
Correct answer: 0.01 torr- A. Moving e- accelerate towards the nucleus
- B. Continuous spectrum
- C. behavior of electron remain unexplained
- D. all
Explanation: Rutherford's planetary model could not explain why an accelerating electron did not continuously radiate energy and spiral into the…
Correct answer: all- A. 9.11 x 10^-31 Kg
- B. Cast shadow
- C. Heat up the platinum foil
- D. Cannot ionize
Explanation: Cathode rays can ionize gases, so the statement that they cannot ionize is false.
Correct answer: Cannot ionize37. Which of the following properties prove that cathode rays are material in nature_________________?
- A. they cast shadow
- B. they possess momentum
- C. they are negatively charged
- D. all of the above
Explanation: Cathode rays possess momentum, showing that they consist of moving particles with mass, namely electrons.
Correct answer: they possess momentum- A. neutrons
- B. protons and electrons
- C. protons
- D. protons and neutrons
Explanation: The atomic number of an element is defined by its number of protons, so every atomic nucleus contains at least one proton.
Correct answer: protons- A. 1.0073
- B. 1.0087
- C. 5.485 x 10^-4
- D. 9.1 x 10^-31
Explanation: The conversion from kg to a.m.u is; 1 a.m.u= 1.66 x 10-27 The mass of an electron is 9.11x10-31 kg; this value should be learned for the…
Correct answer: 5.485 x 10^-4- A. 1.602 x 10^-31 C
- B. 1.602 x 10^-27 C
- C. 1.602 x 10^-19 C
- D. 1.602 x 10^-11 C
Explanation: This is a factual recall question. The charge on a proton is equal to +1e, where e is the elementary charge having a value of 1.602 x…
Correct answer: 1.602 x 10^-19 C