Which two developments remove the drawbacks of Bohr's model?

The uncertainties in the velocities of particles $A$ and $B$ are $0.05 \, m/s$ and $0.02 \, m/s$,respectively. If the mass of particle $B$ is five times that of particle $A$,then the ratio of the uncertainties in their positions $\left( \frac{\Delta x_A}{\Delta x_B} \right)$ is equal to:

Provide the equation for a system where the energy of an atom or molecule does not change with time.

What is the uncertainty product $\Delta v \cdot \Delta x$ for a particle of mass $1 \ mg$? What does this imply?

The uncertainty in the determination of the position of a small ball of mass $10 \ g$ is $10^{-33} \ m$. With what percentage of accuracy can its speed be measured,if it has a speed of $52.5 \ m \ s^{-1}$? (Given: $h = 6.6 \times 10^{-34} \ J \ s$)

If the uncertainty in velocity of electron $(\Delta v)$ is $0.1 \ m/s$,the uncertainty in its position $(\Delta x)$ is (given: $m_e = 9.1 \times 10^{-31} \ kg$)