Comparing Electric and Gravitational Forces

What is the electric potential at point A?

• +50V

• +60V

• +70V

• +40V

What is the electric potential at point B?

• +60V

• +70V

• +80V

• +90V

Given that sphere Y has a positive charge, what is the sign of the charge on sphere X?

• Positive

• Negative

• Neutral

• Cannot be determined from the isolines

How do the magnitudes of the charges on spheres X and Y compare?

• Sphere X has a larger magnitude charge than sphere Y.

• Sphere Y has a larger magnitude charge than sphere X.

• Both spheres have charges of equal magnitude.

• The magnitudes cannot be compared from the given isolines.

How do the magnitudes and signs of the charges on spheres X and Y compare?

• Both spheres have positive charges, and sphere Y has a larger magnitude charge than sphere X.

• Both spheres have negative charges, and sphere Y has a larger magnitude charge than sphere X.

• Sphere X has a positive charge and sphere Y has a negative charge, with equal magnitudes.

• Both spheres have positive charges, and sphere X has a larger magnitude charge than sphere Y.

Why do gravitational potential isolines around two masses have similar shapes to electric potential isolines around two positive electric charges?

• Both gravitational and electric fields are always attractive, leading to similar field line patterns.

• Moving a test mass in a gravitational field changes its gravitational potential, analogous to moving a test charge in an electric field changing its electric potential, and masses are always positive.

• Gravitational potential is directly proportional to electric potential, ensuring identical isoline configurations.

• The inverse square law applies only to electric forces, but not to gravitational forces, causing the similarity.

What is a specific similarity between electric and gravitational forces, not generally applicable to all forces?

• Both forces always cause acceleration.

• Both forces can do positive and negative work.

• The magnitude of both forces is proportional to the inverse square of the distance between the interacting objects.

• Both forces are always attractive.

What is a key difference between electric and gravitational forces?

• Electric forces are always attractive, while gravitational forces can be repulsive.

• Electric forces can be either attractive or repulsive, while gravitational forces are always attractive.

• Gravitational forces are much stronger than electric forces.

• Electric forces act over short distances, while gravitational forces act over long distances.

A proton moves from an initial position with electric potential V_B to a final position with electric potential V_A. What is the change in the electric potential energy of the proton-spheres system?

• q(V_B - V_A)

• q(V_A - V_B)

• (V_A - V_B) / q

• (V_B - V_A) / q

A proton with charge q is displaced a distance d by an electric force through an average electric field of magnitude E_avg. What is the total work done on the proton by the electric field?

• q * E_avg / d

• E_avg * d / q

• q * E_avg * d

• d / (q * E_avg)