Calculate the answer up to appropriate numbers of significant digits.
(a): Calculation of mass of proton to mass of electron ratio
Now in the input numbers, 1.67 has 3 significant digits and 9.1096 has 5. Therefore, according to quotient rule, the result should be confined to 3 sig figs. Therefore, drop the 3 at 1000th place, the result should be 1.83 × 103. (No unit remember).
b: Calculating charge to mass ratio of electron
Now there are 2 significant digits in 1.6 and 5 in 9.1096. So according to rule, the result should be confined to 2 sig figs. Therefore, dropping 5 and adding 1 in the result, we have, 1.8 × 1011 C/kg is the answer.