Question

A certain moving electron has a kinetic energy of 0.991 × 10−19 J. Calculate the speed necessary for the electron to have this energy. The mass of an electron is 9.109 × 10−31 kg. Answer in units of m/s.

Answer 1

Answer:

4.66 × 10^5 m/s.

Explanation:

Given:

Mass of the electron, m = 9.109 × 10^−31 kg

KE = 0.991 × 10^−19 J.

Kinetic energy, KE = 1/2 × m × v^2

v = sqrt((2 × KE)/m)

= sqrt(2.176 × 10^11)

= 4.66 × 10^5 m/s.

Answer 2

Answer: The speed necessary for the electron to have this energy is 466462 m/s

Explanation:

Kinetic energy is the energy posessed by an object by virtue of its motion.

$K.E=\frac{1mv^2}{2}$

K.E= kinetic energy = $0.991\times 10^{-19}J$

m= mass of an electron = $9.109\times 10^{-31}kg$

v= velocity of object = ?

Putting in the values in the equation:

$0.991\times 10^{-19}J=\frac{1\times 9.109\times 10^{-31}kg\times v^2}{2}$

$v=466462m/s$

The speed necessary for the electron to have this energy is 466462 m/s