An electron was accelerated from rest through a potential difference of 9900 V.What is its speed?

Question

Quizplus · Accepted Answer

The kinetic energy gained by the electron when it's accelerated through a potential difference is given by

KE = qV

Where q is the charge on the electron and V is the potential difference.

Substituting the given values, we get

KE = (1.6 × 10^-19 C) × 9900 V = 1.584 × 10^-15 J

The kinetic energy can also be expressed as

KE = (1/2)mv^2

Where m is the mass of the electron and v is its final speed.

Substituting the known values, we get

v = √(2KE/m) = √(2 × 1.584 × 10^-15 J/9.11 × 10^-31 kg) = 5.9 × 10^7 m/s

Therefore, the correct answer is (A) 5.9 × 10^7 m/s.

An Electron Was Accelerated from Rest Through a Potential Difference