JEE Advanced 2015 · Paper 2 · Physics Q8

← JEE Advanced 2015 · Paper 2

PhysicsInteger+4Question 8 of 60

An electron in an excited state of $\ce{Li^{2+}}$ ion has angular momentum $3h/2\pi$ . The de Broglie wavelength of the electron in this state is $p\pi a_0$ (where $a_0$ is the Bohr radius). The value of $p$ is

Your answer

Answer and worked solution

Official answer: 2

Orbit. $L=\dfrac{3h}{2\pi}$ means $n=3$ . For Li²⁺ ( $Z=3$ ), $r=\dfrac{n^2a_0}Z=3a_0$ .

de Broglie wavelength. $2\pi r=n\lambda$ , so
$\lambda=\frac{2\pi(3a_0)}3=2\pi a_0.$
So $p=2$ .

Answer: 2

Topics:Bohr model and hydrogen spectrum de Broglie waves

← Previous question Next question →

JEE Advanced 2015 · Paper 2, Physics question 8