MHT CET202311 May 2023Morning ShiftPhysicsCenter of Mass, Momentum and CollisionActual
An electron moving with velocity 1.6 10^7 ~m / s has wavelength of 0.4 Å . The required accelerating voltage for the electron motion is [charge on electron =1.6 10⁻¹⁹ C , mass of electron .=9 10⁻³¹ ~kg ]
Options
- A7.2 10^3 ~V
- B7.2 10^2 ~V
- C7.2 ~V
- D7.2 10⁻² ~V
Correct answer
B. 7.2 10^2 ~V
Step-by-step solution
When an electron is accelerated through a voltage its kinetic energy is converted into electric potential energy: aligned K & = U & 1 2 mv ^2= eV V & = mv ^2 2 e & V = (9 10⁻³¹ ) (1.6 10^7 )^2 2 1.6 10⁻¹⁹ =7.2 10^2 ~V aligned