A particle is moving 5 times as fast as an electron. The ratio of the de-Broglie wavelength of the particle to that of the electron is $1.878 × 10^4$. The mass of the particle is close to:

$9.7×10^{-28} kg$

$\text{Debroglie Wavelength } \lambda = \frac{h}{p}$

$\frac{\lambda_1}{\lambda_2} = \frac{p_2}{p_1} = \frac{m_2}{m_1} \frac{v_2}{v_1} = 5 \frac{m_2}{m_1}$

$m_2 = \frac{m_1}{5} \frac{\lambda_1}{\lambda_2}= \frac{9.11 \times 10^{-31}}{5 \times 1.878\times10^{-4}} = 9.7 \times 10^{-28} kg$