Bohr's Postulates

Q.

According to Bohrs theory of Hydrogen atom, for the electron in the $n^{th}$ allowed orbit the kinetic energy is proportional to $\frac{1}{n^2}$. (True / False)

1. True
2. False

Q. According to Bohr's postulate, electrons revolve around the nucleus in certain definite circular paths called stationary orbits in which they do not radiate energy.

1. False
2. True

Q. Electron revolves around nucleus only in those orbits for which the angular momentum is an integral multiple of $\frac{h}{2\pi }$.

1. False
2. True

Q. Ionisation potential of $L{i}^{++}$ in ground state is

1. 13.6 V
2. 122.4 V
3. 54.4 V
4. 3.4 V

Q. Electron revolves around nucleus only in those orbits for which the angular momentum is an integral multiple of $\frac{h}{2\pi }$.

1. False
2. True

Q. Which of the following is incorrect about motion of electron in Bohr atom?

1. Motion is uniform and speed remains constant in an orbit
2. Velocity is constant
3. Total energy is same for all orbits
4. Ratio of K.E & total energy is 1:1

Q. An electron present in an atom can move from a lower energy level to a level of higher energy by absorbing the appropriate energy.

1. False
2. True

Q. Magnetic dipole moment corresponding to motion of electron in second excited state of $H{e}^{+}$ ion is

1. $\frac{eh}{4m\pi }$
2. $\frac{3eh}{4m\pi }$
3. $\frac{eh}{2m\pi }$
4. $\frac{5eh}{4m\pi }$

Q. The magnetic moment $\left(\mu \right)$ of an electron revolving around the nucleus, varies with principal quantum number $n$ as,

Q. In a hydrogen atom, the electron jumps from one stationary orbit for which n=1 to an orbit for which n=3. If the angular momenta of these levels are $L_i$ and $L_f$ respectively, what is the ratio $\frac{L_f}{L_i}$ ?

1. 2:1
2. 3:1
3. 3:2
4. 4:1