Question

Pick out electron’s charge to mass ratio’s value from the options.

(a) 1.758820 × 10^11 C kg^-1

(b) 1.758820 × 10^11 C kg

(c) 1.758823 × 10^11 C kg

(d) 1.708820 × 10^11 C kg

I have been asked this question in a national level competition.

Query is from Discovery of Sub-atomic Particles in division Structure of Atom of Chemistry – Class 11

Answer 1

Right choice is (a) 1.758820 × 10^11 C kg^-1

Easy explanation: A British physicist J. J. Thomson carried out experiments and observed the deflections made by electrons in an electric or magnetic field. He finally calculated electron’s charge to mass ratio as e/me = 1.758820 × 10^11 C kg^-1. The units of charge and mass are in coulomb and kg respectively.