AP EAMCET202125 Aug 2021Evening ShiftPhysicsAtomic PhysicsActual
The ratio of speed of electrons in the first excited state of hydrogen atom to the speed of light in vacuum is [Given, Planck's constant =6.625 10⁻³⁴ Js and permittivity of free space is 8.85 10⁻¹² Fm ⁻¹ ]
Options
- A5 10⁻³
- B7.3 10⁻³
- C3.6 10⁻³
- D36.5 10⁻³
Correct answer
C. 3.6 10⁻³
Step-by-step solution
Velocity of electron in the nth orbit of an atom is given by v= 2 k e^2 h Z n where, 2 k e^2 h is a constant quantity and Z is atomic number. Hence, speed of electron in first excited state (n = 2) is aligned v & =2.188 10^6 1 2 (Z=1, for hydrogen atom ) & =1.094 10^6 ~ms ⁻¹ aligned Ratio of speed of electron in lst excited state to aligned the speed of light in vacuum & = 1.094 10^6 3 10^8 & =0.364 10⁻² & =3.6 10⁻³ aligned