Question

In which year, J.J. Thomson discovered the electron, the first subatomic particle.
A) 1876
B) 1877
C) 1888
D) 1897

Answer 1

Hint:We must remember that the electron is a subatomic particle with symbols of ${e^ - }$ or ${\beta ^ - }$. Electrons carry negative charge of $ - 1.6 \times {10^{ - 19}}Coulomb$. Electrons play an important role in numerous physical phenomena such as thermal conductivity, electricity etc.

Complete step by step answer: Sir Joseph John Thomson was a British physicist and Nobelist in Physics, credited with the invention of the electron, the primary elementary particle to be discovered. In 1897, J.J. Thomson discovered the electron, the primary elementary particle.
In 1897, Thomson showed that cathode rays were composed of previously unknown charged particles (now called electrons), which he calculated must have bodies much smaller than atoms and a really large charge-to-mass ratio. Thomson is additionally credited with finding the primary evidence for isotopes of a stable (non-radioactive) element in 1913, as a part of his exploration into the composition of canal rays (positive ions). His experiments to work out the character of charged particles, with Francis William Aston, were the primary use of mass spectrometry and led to the event of the mass spectrometer.

Therefore, the option D is correct .


Note: We also remember that Dalton's atomic theory explains the law of conservation of mass, law of constant composition and all of multiple proportions very successfully. There are three kinds of subatomic particles that were discovered in the nineteenth and the twentieth century like electron, proton and neutron. Each of these subatomic particles involved different sets of experiments which were conducted by different scientists to prove the existence of these particles.