Question

A "free" electron and a "free" proton are placed in an identicalelectric field. Which of the following statements are true? (Selectall that apply.)Each particle is acted upon by the sameelectric force and has the same acceleration.The magnitude of the acceleration of theelectron is greater than that of the proton.The electric force on the proton isgreater in magnitude than the electric force on the electron, butin the opposite direction.Both particles have the sameacceleration.The electric force on the proton is equalin magnitude to the electric force on the electron, but in theopposite direction.Can anyone explain why each of these statements is either false ortrue?

Answer 1

Explanation:

The charge on an electron and proton is -e and +e respectively. The electric force between charges is given by :

$F=\dfrac{kq_1q_r}{r^2}$

The mass of electron is, $m_e=9.1\times 10^{-31}\ kg$

The mass of proton is, $m_p=1.67\times 10^{-27}\ kg$

The force applied by proton to electron is same as the force applied by an electron to proton due to Newton's third law of motion.

Acceleration, $a=\dfrac{F}{m}$

It is clear that the mass of proton is more than the mass of electron, so, the acceleration of proton is less than the acceleration of electron.

So, the correct options are :

• The electric force on the proton is equal in magnitude to the electric force on the electron, but in the opposite direction
• The magnitude of the acceleration of the electron is greater than that of the proton.