An alpha particle (mass = 6.6 x 10²⁴ g) emitted by radium travels at 3.4 x 10⁷ ± 0.1 x 10⁷ mi/h.
(a) What is its de Broglie wavelength (in meters)?
(b) What is the uncertainty in its position?

Respuesta :

Answer:

For a: The De-Broglie wavelength of the given particle is [tex]2\times 10^{-10}m[/tex]

For b: The uncertainty in the position is [tex]3.56\times 10^{-14}m[/tex]

Explanation:

  • For a:

To calculate the wavelength of a particle, we use the equation given by De-Broglie's wavelength, which is:

[tex]\lambda=\frac{h}{mv}[/tex]

where,

[tex]\lambda[/tex] = De-Broglie's wavelength = ?

h = Planck's constant =

m = mass of the alpha particle =

v = velocity of alpha particle = [tex]3.4\times 10^7mi/h=1.52\times 10^7m/s[/tex]  (Conversion factors used:  1 mile = 1609.34 m  &  1 hr = 3600 s)

Putting values in above equation, we get:

[tex]\lambda=\frac{6.6\times 10^{-34}Js}{6.6\times 10^{-27}kg\times 1.52\times 10^7m/s}\\\\\lambda=6.58\times 10^{-15}m[/tex]

Hence, the De-Broglie wavelength of the given particle is [tex]2\times 10^{-10}m[/tex]

  • For b:

The equation representing Heisenberg's uncertainty principle follows:

[tex]\Delta x.\Delta p\geq \frac{h}{2\pi}[/tex]

where,

[tex]\Delta x[/tex] = uncertainty in position = ?

[tex]\Delta p[/tex] = uncertainty in momentum  = [tex]m\Delta v[/tex]

m = mass of the alpha particle = [tex]6.6\times 10^{-27}kg[/tex]

[tex]\Delta v[/tex] = uncertainty in speed = [tex]0.1\times 10^7mi/hr=4.47\times 10^5m/s[/tex]

h = Planck's constant = [tex]6.6\times 10^{-34}kgm^2/s[/tex]

Putting values in above equation, we get:

[tex]\Delta x=\frac{6.6\times 10^{-34}kgm^2/s}{2\times 3.14 \times 6.6\times 10^{-27}\times kg 4.47\times 10^{5}m/s}\\\\\Delta x=3.56\times 10^{-14}m[/tex]

Hence, the uncertainty in the position is [tex]3.56\times 10^{-14}m[/tex]