A polythene piece rubbed with wool is found to have a negativecharge of 3 × 10–7 C. (a) Estimate the number of electrons transferred (from which towhich?) (b) Is there a transfer of mass from wool to polythene?
a)
Since, the polythene have a negative charge of 3 × 10 − 7 C thus, some amount of electrons from wool get transferred into polythene such that wool becomes positively charged and polythene becomes negatively charged.
Total charge on an object is given as,
q = n e
Where, n is the number of electrons and e is the charge on an electron.
By substituting the values in the above equation, we get
− 3 × 10 − 7 = n ( − 1.6 × 10 − 19 ) n = 1.875 × 10 12
Thus, the number of electrons transferred from wool to polythene is 1.875 × 10 12 .
b)
Since, electrons also have some mass and here some electrons are transferred from wool to polythene
Thus, some amount of mass is transferred from wool to polythene.
The amount of mass transferred from wool to polythene is given as,
m = n m e
Where, m e is the mass of an electron.
By substituting the values in the above equation, we get
m = 1.875 × 10 12 × 9.1 × 10 − 31 kg = 1.71 × 10 − 18 kg
Thus, a negligible mass 1.71 × 10 − 18 kg has been transferred from wool to polythene.
a)
Since, the polythene have a negative charge of
Total charge on an object is given as,
Where,
By substituting the values in the above equation, we get
Thus, the number of electrons transferred from wool to polythene is
b)
Since, electrons also have some mass and here some electrons are transferred from wool to polythene
Thus, some amount of mass is transferred from wool to polythene.
The amount of mass transferred from wool to polythene is given as,
Where,
By substituting the values in the above equation, we get
Thus, a negligible mass
