Question

In Milikan's experiment, static electric charge on the oil drops has been obtained by shining X–rays. If the static electric charge on the oil drop is –1.282 × $10^{-18}$ C, calculate the number of electrons present on it.

Answer 1

"$Charge\quad carried\quad by\quad the\quad oil\quad drop\quad =\quad 1.282\quad \times \quad { 10 }^{ -18 }\quad C$

$Charge\quad carried\quad by\quad one\quad electron\quad =\quad 1.6022\quad \times \quad { 10 }^{ -19 }\quad C$

$\therefore \quad Electrons\quad present\quad on\quad the\quad oil\quad drop\quad carrying\quad 1.282\quad \times \quad { 10 }^{ -18 }\quad C\quad charge$

$=\quad \frac { 1.282\quad \times \quad { 10 }^{ -18 }\quad C }{ 1.6022\quad \times \quad { 10 }^{ -19 }\quad C }$

$=\quad 0.8001\quad \times \quad 10\\ =\quad 8.0$"

Answer 2

Answer:

-1. 282÷-1.602 = 0.8002 then take account of orders so 10^-18/10^-19 = 10 so n = 8 so we say no of electrons ( n) = 8