The de - Broglie wavelength of a ball of mass 120 g moving at a speed of `"20 m s"^(-1)` is (Planck's constant `h=6.6xx10^(-34)Js`)

Options

A. `3.5 xx 10^(-34) m `
B. `2.8 xx 10^(-34) m `
C. `1.2 xx 10^(-34) m `
D. `2.1 xx 10^(-34) m `

Answer

B

Explanation

de Broglie wavelegth of a ball is `lamda = h /(mv)`
where m is the mass and v is the speed of the ball.
`:. lamda=(6.6 xx10^(-34)Js)/((120 xx 10^(-3) kg)(20ms^(-1)))= 2.8 xx 10^(-34)m`