Question 11

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?

Answer

(a) When polythene is rubbed against wool, a number of electrons get transferred from wool to polythene. Hence, wool becomes positively charged and polythene becomes negatively charged.

Amount of charge on the polythene piece, q = −3 × 10^{−7} C

Amount of charge on an electron, e = −1.6 × 10^{−19} C

Number of electrons transferred from wool to polythene = n

n can be calculated using the relation, q = ne

=

= 1.87 × 10^{12}

Therefore, the number of electrons transferred from wool to polythene is 1.87 × 10^{12}.

(b) Yes. There is a transfer of mass occur. This is because an electron has mass,

as we know

m_{e} = 9.1 × 10^{−3} kg

Total mass transferred from wool to polythene,

m = m_{e} × n

= 9.1 × 10^{−31} × 1.85 × 10^{12}

= 1.706 × 10^{−18} kg

Hence, a negligible amount of mass is transferred from wool to polythene.

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Ankit Yadav
2019-06-21 06:45:55

Thanks

Anushka
2019-06-09 08:36:06

Thank you, I got it ð

2019-01-04 23:30:29

me = 9.1 Ã 10â3 kg y sahi hai

Ujjwal
2018-09-22 19:09:40

How u get Me value there

Aaishu
2018-05-16 20:33:49

I sincerely apologise to have given an incorrect comment previously. Regards.

Aaishu
2018-05-16 20:31:41

There's also a part (c) in the question. Please check. Regards

Savithri
2018-03-30 11:11:37

Its totally wrong

DEVYANI
2018-03-24 20:54:19

no due to wrong multiplication

Why
2018-03-05 21:25:20

nooooo

Debosmit
2017-02-08 21:50:19

Why is n is having a fractional value when \'n\' must always be a whole number according to quantization theory? Please explain the fault in the numerical.

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