Question
Question: The ratio of the speed of the electron in the first Bohr orbit of hydrogen and the speed of light is...
The ratio of the speed of the electron in the first Bohr orbit of hydrogen and the speed of light is equal to (where e, h and c have their usual meanings) –
A
2phc/e2
B
e2 c/2ph
C
e2 h/2pc
D
e2 /2e0hc
Answer
e2 /2e0hc
Explanation
Solution
v = h2πe2k(nZ)
Q Z = 1, n = 1
\ v = h2πe2k cv=ch2πe2k
Žch2πe2(4πε01)Ž cv=2ε0che2