Question
Physics Question on Atoms
In hydrogen atom, radius of the smallest orbit of the electron is a0, the radius of the third orbit is
A
9 a0
B
a0
C
3 a0
D
6 a0
Answer
9 a0
Explanation
Solution
The radius of the nth orbit is given by the formula:
rn = n2 * a0 .
In this case, we are looking for the radius of the third orbit. Plugging in n = 3 into the formula, we get:
r3 = 32 * a0
r3 = 9 * a0
Therefore, the radius of the third orbit is 9 times the Bohr radius, or 9 a0.
Hence, the correct answer is (A) 9 a0.