JEE Mains · Physics · STD 12 - Atoms
- JEE Mains 2021
- Hard
- Numerical
In Bohr's atomic model, the electron is assumed to revolve in a circular orbit of radius \(0.5 \times 10^{-10}\,m\). If the speed of electron is \(2.2 \times 10^{6} \;{m} / {s}\), then the current associated with the electron will be \(....\,\times 10^{-2} \;{mA}\). [Take \(\pi\) as \(\left.\frac{22}{7}\right]\)
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(112\)
Step-by-step Solution
Detailed explanation
time taken \(=\frac{2 \pi r }{\text { speed }}\)
\(=\frac{2 \times \pi \times 5 \times 10^{-11}}{2.2 \times 10^{6}}\)
\(=\frac{2 \times 22 \times 10 \times 5 \times 10^{-11}}{7 \times 22 \times 10^{6}}\)
\(=\frac{10}{7} \times 10^{-16}\)
Current \(\frac{ q }{ t }\left(1 e =1.6 \times 10^{-19} C \right)\)
\(=\frac{1.6 \times 10^{-19}}{10 \times 10^{-16}} \times 7\)
\(=\frac{1.6}{100} \times 10^{-3} \times 7\)
\(=112 \times 10^{-5} A\)
\(=112 \times 10^{-5} \times 1000 m A\)
\(=1.12 mA\)
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