Modern Physics Questions and Answers – Page 5

The correct answer is Option A — Higgs Boson. The Higgs Boson is nicknamed the 'God Particle' because it was theorized to be responsible for giving mass to all other particles. It was discovered at CERN's Large Hadron Collider (LHC) in 2012.

Why other options are wrong:

Option B (Neutron): The neutron is a neutral subatomic particle found in the nucleus. It is NOT called the God Particle.

Option C (Pion): A pion (pi-meson) is a subatomic particle involved in the nuclear force. It is not called the God Particle.

Option D (Positron): A positron is the antimatter counterpart of an electron (positive charge). It is not called the God Particle.

The correct answer is Option D — 9.1 × 10⁻³¹ kg. The electron is the lightest of the three fundamental subatomic particles (electron, proton, neutron). Its mass is approximately 9.1 × 10⁻³¹ kg (more precisely 9.10938 × 10⁻³¹ kg). This is a fundamental constant in physics used extensively in atomic and nuclear calculations.

Why other options are wrong:

Option A (9.1 × 10⁻²⁸ kg): This is not the correct value for electron mass. It is 1000 times larger than the actual electron mass.

Option B (1.67 × 10⁻²⁷ kg): This is the mass of a PROTON, not an electron. The proton is about 1836 times heavier than the electron.

Option C (1.67 × 10⁻³¹ kg): This is an incorrect value. While the exponent (-31) is correct, the coefficient 1.67 belongs to the proton/neutron mass.

The correct answer is Option C — J.J. Thomson.

Sir Joseph John Thomson discovered cathode rays (electrons) in 1897 through experiments with cathode ray tubes. He proved that cathode rays are streams of negatively charged particles, which are now called electrons. He measured the charge-to-mass ratio (e/m) of electrons and proved they are fundamental subatomic particles. For this discovery, he was awarded the Nobel Prize in Physics in 1906.

Why other options are wrong:

Option A — Ernest Rutherford: Rutherford discovered the nuclear model of the atom (1911) and the proton. He did NOT discover cathode rays or electrons.

Option B — Goldstein: Eugen Goldstein discovered canal rays (anode rays / positive rays) in 1886. He discovered proton-like positive particles, NOT electrons or cathode rays.

Option D — James Chadwick: Chadwick discovered the neutron in 1932. He had nothing to do with the discovery of cathode rays or electrons.