Electric Forces and Fields Quiz

Two point charges, +q and −q, are placed a small distance apart. What is the nature of the force between them?

• Repulsive

• Attractive

• Zero

• Gravitational

If the distance between two point charges is doubled, the electric force between them will become:

• Four times

• Half

• One-fourth

• Double

The electric field lines due to a positive point charge are:

• Radially inward

• Radially outward

• Circular

• Parallel straight lines

The SI unit of electric field intensity is:

• Newton (N)

• Coulomb (C)

• Volt (V)

• Newton per Coulomb (N/C)

(Numerical) A test charge of +2μC experiences a force of 4×10−3N in an electric field. The magnitude of the electric field at that point is:

• 2×10−3N/C

• 8×10−3N/C

• 2×103N/C

• 8×103N/C

The superposition principle for electric forces states that the total force on a charge due to multiple charges is the:

• Scalar sum of individual forces

• Vector sum of individual forces

• Product of individual forces

• Average of individual forces

If three identical positive charges are placed at the corners of an equilateral triangle, the net force on the charge at the centroid is:

• Directed towards one of the corners

• Directed away from one of the corners

• Zero

• Parallel to one of the sides

An electric dipole consists of:

• Two identical positive charges separated by a small distance

• Two identical negative charges separated by a small distance

• Two equal and opposite charges separated by a small distance

• One positive and one negative charge at the same point

The direction of the electric dipole moment is:

• From the positive charge to the negative charge

• From the negative charge to the positive charge

• Perpendicular to the line joining the charges

• Along the direction of the electric field

(Numerical) An electric dipole has charges of +10μC and −10μC separated by 2mm. Its dipole moment is:

• 2×10−8Cm

• 2×10−5Cm

• 20×10−8Cm

• 20×10−5Cm