Question

A particle of mass $1mg$ has the same wavelength as the electron moving with a velocity of $3\times {10}^{6}m{s}^{-1}$. The velocity of the particle is (mass of electron =$9.1\times {10}^{-31}$ kg).

• A. $2.7\times {10}^{-21}m{s}^{-1}$
• B. $2.7\times {10}^{-18}m{s}^{-1}$
• C. $9\times {10}^{-2}m{s}^{-1}$
• D. $3\times {10}^{-31}m{s}^{-1}$

Answer 1

The correct option is B $2.7\times {10}^{-18}m{s}^{-1}$

${\lambda }_{particle}={\lambda }_{electron}$

$\frac{h}{m_p{V}_p}=\frac{h}{m_e{V}_e}$

or, $m_p{V}_p=m_e{V}_e$

${10}^{-6}\times V_p=9.31\times {10}^{-31}\times 3\times {10}^6$

$\therefore V_p=2.7\times {10}^{-18}m{s}^{-1}$