The velocities of two particles $A$ and $B$ are $0.05 \ ms^{-1}$ and $0.02 \ ms^{-1}$ respectively. The mass of $B$ is five times the mass of $A$. The ratio of their de-Broglie's wavelength is

$A$ $200 \ g$ golf ball is moving with a speed of $5 \ m$ per hour. The associated wavelength is $(h = 6.625 \times 10^{-34} \ J \ s)$.

In the ground state of a hydrogen atom,an electron absorbs $1.5$ times the minimum energy $\left(2.18 \times 10^{-18} \ J\right)$ required to escape from the atom. The wavelength of the emitted electron (in $m$) is $\left(m_e = 9 \times 10^{-31} \ kg\right)$.

The de Broglie wavelength of a tennis ball of $60 \ g$ moving with a velocity of $10 \ m/s$ is approximately

Calculate the wavelength of an electron if its mass is $9.1 \times 10^{-31} \, kg$,its velocity is $1/10$ of the speed of light,and the value of Planck's constant $h$ is $6.626 \times 10^{-34} \, J \cdot s$.

For which of the following does the mathematical expression $\lambda = \frac{h}{p}$ stand?