Question

1. A hydrogen nucleus which has a charge +e, is situated to the left of a sulfate ion, which has a charge -2e. Which statement is true?

A) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is equal to the force exerted on the sulfate ion.

B) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is greater than the force exerted on the sulfate ion.

C) The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is less than the force exerted on the sulfate ion.

D) The electrical force experienced by the hydrogen nucleus is to the right, and the magnitude is equal to the force exerted on the sulfate ion.

2. An electron and a proton are released simultaneously from rest and start moving toward each other due to their electrostatic interaction. No other forces are present. Which of the following statement is true?

A) the net force on the proton is smaller than the net force on the electron

B) the net force on the proton is equal to the net force on the electron.

C) the net acceleration of the electron is smaller than the net acceleration of the proton.

D) the net acceleration of the electron is equal to the net acceleration of the proton.

3. If an electron is moving in the direction of the magnetic field lines

A) it feels a magnetic force parallel to the magnetic field and gains no kinetic energy.

B) it feels a magnetic force perpendicular to the magnetic field and gains kinetic energy.

C) it feels no magnetic force but gains kinetic energy.

D) it feels no magnetic force and gains no kinetic energy.

Answer 1

1)Correct Ans is:

D) The electrical force experienced by the hydrogen nucleus is to the right, and the magnitude is equal to the force exerted on the sulfate ion.

Since the chares are +e and -2e, e will get attracted to -2e to the right, and the force will be same for both.

2)Correct Ans is;

B) the net force on the proton is equal to the net force on the electron.

Since, F = k q1q2/r^2

and from Newtons second law will be equal for both.

3)Correct Ans is:

D) it feels no magnetic force and gains no kinetic energy.

As, F(magnetic) = q v B sin(theta)

theta = 0 => F = 0