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DUAL NATURE OF RADIATION AND MATTER — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsDUAL NATURE OF RADIATION AND MATTER2 Marks
Question
Explain how the mass of an electron can be found using Millikan's oil drop experiment.
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Answer

→Millikan introduced a new electric charge to the oil droplet with an electron and calculated the electric charge differently.
→Millikan observed that the electric charge on an oil droplet was always an integral multiple of $1.6 \times 10^{-19} C$.
→Thus, the charge of an electron should be $1.6 \times 10^{-19} C$.
→Putting the value $e=1.6 \times 10^{-19} C$, in the specific charge $\frac{e}{m}=1.76 \times 10^{11} \frac{ C }{ kg }$, the mass of the electron is found to be $m=9.1 \times 10^{-31} kg$.

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