Question

An electron of mass 9 × 10–31 kg is moving in a straight line path with a velocity of 6 × 107 ms–1. The
momentum of electron is :
(A) 5.4 × 10–23 Ns (B) 5.4 × 10–24 Ns (C) 4.5 × 10–23 Ns (D) 0.5 × 10–24 Ns

Answer 1

Answer :

• The momentum of the electron with mass 9 × 10⁻³¹ kg and moving with the velocity of 6 × 10⁷ m/s , p = 5.4 × 10-²⁵ kg m/s

Explanation :

Given :

• Mass of the electron , m = 9 × 10⁻³¹ kg.

• Velocity of the electron along with straight line path , v = 6 × 10⁷ m/s

Knowledge required :

By definition , momentum is the product of the mass and velocity .

So ,

⠀⠀⠀⠀⠀⠀⠀⠀⠀p = mv

Where,

• p = Momentum
• m = Mass
• v = Velocity

Solution :

Now using the formula for momentum and substituting the values in it, we get :

==> p = mv

==> p = 9 × 10⁻³¹ × 6 × 10⁷

==> p = (9 × 6) × (10⁻³¹ × 10⁷)

==> p = 54 × 10^(-31 + 7)⠀⠀[a^n + a^b = a^(n + b]

==> p = 54 × 10⁻²⁴

==> p = 5.4 × 10⁻²⁵

∴ p = 5.4 × 10⁻²⁵ kg m/s.

Therefore,

• The momentum of the electron is 5.4 × 10⁻²⁵ kg m/s.

Answer 2

Answer:

5.4 × 10–24 Ns