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MHT CET 2021 (21 Sep, Shift 2) · Electric Charge & Coulomb's Law

Electric Charge & Coulomb's Law question from MHT CET 2021 (21 Sep, Shift 2)

Q51MHT CET 2021 · 21 SEP · SHIFT 2Easy

Electric Charge & Coulomb's Law

When a piece of polythene is rubbed with wool, a negative charge of 4×10−7 C4 \times 10^{-7}\text{ C} is developed on the polythene. The number of electrons transferred from wool to polythene is [e=1.6×10−19 C][e = 1.6 \times 10^{-19}\text{ C}]

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Answer: (d)

  1. Quantisation of charge: q=ne⇒n=qeq = ne \Rightarrow n = \dfrac{q}{e}.
  2. n=4×10−71.6×10−19=2.5×1012n = \dfrac{4\times10^{-7}}{1.6\times10^{-19}} = 2.5\times10^{12}
  3. So the answer is (d) 2.5×10122.5\times10^{12}.
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