Question

A green ball weighs $75g$; it is travelling towards observer at a speed of $400cm/sec$. The ball emits light of wavelength $5\times {10}^{-5}cm$. Assuming that the error in the position of ball is the same as wavelength of itself, calculate error in the momentum of the green ball.

Answer 1

$\Delta x\cdot \Delta p\ge \frac{h}{4\pi }$
$\Delta p\ge \frac{h}{4\pi \Delta x}$
$\Delta p\ge \frac{h}{4\pi \lambda }$
$\Delta p=\frac{6.626\times {10}^{-27}}{4\times 3.14\times 5\times {10}^{-5}}=1.055\times {10}^{-23}$.