Discovery Of Neutron

Overview

Chadwick's Experiment:
Chadwick's experiment for the discovery of the neutron involved bombarding beryllium with alpha particles, leading to the emission of penetrating radiation. These neutral particles were identified as neutrons due to their lack of charge, as confirmed by the charge detector.

Comparison of Sub-Atomic Particles:
When comparing electrons, protons, and neutrons, it's important to note that electrons are negatively charged, protons are positively charged, and neutrons are neutral. Additionally, electrons are much lighter than protons and neutrons, with protons being approximately 1836 times heavier than electrons.

Questions and Answers

  1. What experiment led to the discovery of the neutron?

    The discovery of the neutron was made through Chadwick's experiment where a stream of alpha particles bombarded beryllium and resulted in the emission of neutrons.

  2. Who conducted the experiment that led to the discovery of the neutron?

    James Chadwick conducted the experiment that led to the discovery of the neutron.

  3. What are the properties of neutrons according to the document?

    Neutrons decay into a proton, electron, and neutrino. They cannot ionize gases, are highly penetrating particles, and can expel high-speed protons from certain materials.

  4. How are fast neutrons different from slow neutrons?

    Fast neutrons have energy above 1.2 MeV and are used for fission purposes, while slow neutrons have energy below 1eV and are more effective for certain reactions.

  5. What happens when slow-moving neutrons hit copper?

    When slow-moving neutrons hit copper, gamma radiations are emitted, and the copper is converted into zinc.

Multiple-Choice Questions

  1. What is the charge detector's indication of neutrons in Chadwick's experiment?

    a) Positive
    b) Negative
    c) Neutral
    d) Variable
    Answer: c) Neutral

  2. Which particle is rearranged and an extra neutron emitted in Chadwick's experiment?

    a) Helium
    b) Carbon
    c) Beryllium
    d) Nitrogen
    Answer: a) Helium

  3. What happens when slow-moving neutrons hit copper metal?

    a) Alpha particles are emitted
    b) Beta particles are emitted
    c) Gamma radiations are emitted
    d) Neutrons are emitted
    Answer: c) Gamma radiations are emitted

  4. What is the biological application of neutrons due to their intense effects?

    a) Used in food preservation
    b) Used in power generation
    c) Used in cancer treatment
    d) Used in water purification
    Answer: c) Used in cancer treatment

  5. What is the e/m value of an electron as determined by J.J. Thomson's experiment?

    a) 1.7588 x 1011 coulombs kg-1
    b) 2.718 x 19 coulombs kg-1
    c) 3.142 x 1010 coulombs kg-1
    d) 5.669 x 1012 coulombs kg-1
    Answer: a) 1.7588 x 1011 coulombs kg-1