Question

The linear momentum of an electron, initially at rest, accelerated through a potential difference of 100 v is

Answer 1

charge on electron, q = 1.6 × 10^-19 C

electron is accelerated through a potential difference, V= 100 volts

mass of electron, m = 9.1 × 10^-31 Kg

Let P is linear momentum of electron,

so, kinetic energy, K.E = P²/2m

here, kinetic energy = workdone by electron to accelerate through potential difference 100 volts

or, K.E = qV

or, P²/2m = qV

or, P = √{2qVm}

putting values of q, V and m

so, P = √{2 × 1.6 × 10^-19 × 100 × 9.1 × 10^-31}

= √{3.2 × 9.1 × 10^-17 × 10^-31}

= √{29.12 × 10^-48}

= 5.4 × 10^-24 Kgm/s

hence, linear momentum of electron is 5.4 × 10^-24 Kgm/s