An electron and a photon have same wavelength. If p is the momentum of electron and E the energy of photon, the magnitude of p / E in SI unit is

Question

An electron and a photon have same wavelength. If p is the momentum of electron and E the energy of photon, the magnitude of p / E in SI unit is (A) 3.0 × 108 (B) 3.33 × 10-9 (C) 9.1 × 10-31 (D) 6.64 × 10-34

Tardigrade Admin · Accepted Answer

λ=(h/p) (for electron) or p=h / λ and E=(h c/λ) (for photon) ∴ (p/E)=(1/c)=(1/3 × 108) =3.33 × 10-9 s m -1

Q. An electron and a photon have same wavelength. If $p$ is the momentum of electron and $E$ the energy of photon, the magnitude of $p / E$ in SI unit is

$3.0 \times 1 0^{8}$

$3.33 \times 1 0^{- 9}$

$9.1 \times 1 0^{- 31}$

$6.64 \times 1 0^{- 34}$

$λ = \frac{h}{p}$ (for electron)
or $p = h / λ$
and $E = \frac{h c}{λ}$ (for photon)
$∴ \frac{p}{E} = \frac{1}{c} = \frac{1}{3 \times 1 0 ^{8}}$
$= 3.33 \times 1 0^{- 9} s m^{- 1}$

Q. An electron and a photon have same wavelength. If p is the momentum of electron and E the energy of photon, the magnitude of p/E in SI unit is

3.0×108

3.33×10−9

9.1×10−31

6.64×10−34