Question

1. The product of the magnitude of one charge of the dipolar distribution and the distance between the charges is called?

A. the dipole moment

B. the Debye constant

C. the electrical potential energy

D. none of the above

2. Which of the following is not true? The electric force

a. decreases with the inverse of the square of the distance between two charged particles

b. between an electron and a proton is much stronger than the gravitational force between them

c. between two protons separated by a distance d is larger than that between two electrons separated by the same distance d

d. may be either attractive of repulsive

3. A hydrogen atom is composed of a nucleus containing a single proton about which a single electron orbits. The electric force between the two particles is approximately 1 x 10^39 greater than the gravitational force! If we can adjust the distance between the two particles, can we find a separation at which the electric and gravitational force are equal?

a. Yes, we must move the particles farther apart

b. Yes, we must move the particles closer together

c. No, not at any distance

d. None of the above

Answer 1

1. A. The Dipole moment: For charge q and -q separated by a distance d, dipole moment = q(d).

2. C. between two protons separated by a distance d is larger than that between two electrons separated by the same distance d. : According to Coulomb's Law, electric force is proprtional to the product of charges and inversely proportional to the square of the distance between the charges. As charge on electron is the same as that on proton, the force will be the same. Also, like charges repel and unlike charges attract. Lastly, electrical force is much stronger than gravitational force.

3. c. No, not at any distance. Both the forces are inversely proportional to the square of the distance between the particles. So if we increase the distance, both forces decrease by the same ratio such that they never become equal.