Question
Explain how the mass of an electron can be found using Millikan's oil drop experiment.
✓
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 $m=9.1 \times 10^{-31} kg$.
→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 $m=9.1 \times 10^{-31} kg$.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Write a short note on mobility of charge carriers.
Gamma rays and radio waves travel with the same velocity in free space. Distinguish between them in terms of their origin and the main application.
A battery of emf 12V and internal resistance 2 $\Omega$ is connected to a 4 $\Omega$ resistor as shown in the figure.
→- Show that a voltmeter when placed across the cell and across the resistor, in turn, given the same reading.
- To record the voltage and the current in the circuit, why is voltmeter placed in parallel and ammeter in series in the circuit?
If 12 resistances each of $12 \Omega$ resistance are joined in a cubical network, then calculate the equivalent resistance at the corners opposite to diagonals of this network.
→The velocities of two $\alpha-$particles A and B entering a uniform magnetic field are in the ratio 4 : 1. On entering the field they move in different circular paths. Give the ratio of the radii of curvature of the paths of the particles.
→No interference pattern is detected when two coherent sources are infinitely close to each other. Why?
An electronically driven loudspeaker is placed near the open end of a resonance column apparatus. The length of air column in the tube is $80\ cm$. The frequency of the loudspeaker can be varied between $20Hz-2kHz$. Find the frequencies at which the column will resonate. Speed of sound in air $= 320m/s.$
→Answer the following question:
Why should gases be insulators at ordinary pressures and start conducting at very low pressures?
Why should gases be insulators at ordinary pressures and start conducting at very low pressures?
Show that the dimensions of the displacement current $\epsilon_0\frac{\text{d}\phi_\text{E}}{\text{dt}}$ are that of an electric current.
→As temperature increases, the viscosity of liquids decreases considerably. Will this decrease the resistance of an electrolyte as the temperature increases?