Question
Chemistry Question on Discovery of Sub-atomic Particles
The ratio of charge to mass of an electron in coulombs per gram was determined by J.J. Thomson. He determined this ratio by measuring the deflection of cathode rays in electric and magnetic fields. What value did he find for this ratio?
A
−1.76×108 coulombs/g
B
1.76×10−8 coulombs/g
C
−1.76×1010 coulombs/g
D
−1.76×10−10 coulombs/g
Answer
−1.76×108 coulombs/g
Explanation
Solution
Charge of an electron is =−1.6×10−19C Mass of electron is 9.1×10−31kg=9.1×10−28g Thus, Charge/mass ratio is 9.1×10−28−1.6×10−19 =−1.76×108 coulombs /g