Question

${\bf{\blue{QUESTION:}}}$
A polythene piece rubbed with wool is found to have a negative charge of 3 × 10–7 C.

(a) Estimate the number of electrons transferred (from which to which?)

(b) Is there a transfer of mass from wool to polythene?

${\bf{\red{Answer\:with\: Explanation}}}$

Answer 1

Answer:

Given:

Polythene piece is rubbed with wool to get a negative charge of 3 × 10^7 C

To find:

• To estimate the number of electrons transferred
• To estimate if mass transfer took place from wool to polythene

Calculation:

We know that the basic charge (minimum charge available ) is the charge of an electron. Let it be denoted by "e"

$e = - 1.6 \times {10}^{ - 19} c$

Now as per the question , a charge of -3 × 10^(-7) has been acquired by polythene.

Therefore number of electrons gained by polythene surface is :

$n = \dfrac{charge \: gained}{e}$

$= > n = \dfrac{3 \times {10}^{ - 7} }{1.6 \times {10}^{ - 19} }$

$= > n = 1.875 \times {10}^{12}$

Therefore electrons transferred from Wool to Polythene piece.

We know that Mass of each electron is as follows :

$m = 9.1 \times {10}^{ - 31} kg$

So mass is also transferred from Wool to Polythene piece.