What are the units of the Coulomb constant k, which appears in Coulomb's law?

At what separation distance will two charges, each of magnitude 6.0 μC, exert a force of 1.4 N on each other?

Two positive point charges P and Q are fixed at the points shown. The charge of P is greater than that of Q. M is the mid-point between the charges.

The electric field due to the two charges will be zero at a point, other than at infinity, that is

Two equally charged balls of the same mass are suspended from strings and hang apart at an angle as shown.

If the charge on Ball 1 alone were increased, how would the two balls hang?

The diagram below shows two long parallel plates that are oppositely charged. A positive test charge + q is placed along the dotted line XY.

The charge +q is moved from X to Y. Which one of the following best shows the variation with distance d from X of the magnitude F of the force on +q?

Four point charges are held at the four corners of a square as shown below. The charges have equal magnitude and the sign of each charge is also shown.

Which arrow best shows the direction of the resultant electric field at the centre of the square due to the point charges?

Point P is midway between two equal positive charges as shown.

Which one of the following is true of the electric field and electric potential at point P?

	Field	Potential
A	zero	zero
B	non-zero	non-zero
C	zero	non-zero
D	non-zero	zero

The work done on a positive point charge of magnitude 3.0 nC as it is moved at constant speed from one point to another is 12 nJ. The potential difference between the two points is

A charged particle P is accelerated between two charged metal plates X and Y separated by a distance d. The particle starts from rest at plate X.

The kinetic energy of P, when it reaches plate Y, is K. The magnitude of the charge on P is e. The magnitude of the electric field strength between the plates is

A proton and an alpha particle are accelerated from rest through the same potential difference. After acceleration the ratio (KE of alpha particle)/(KE of proton) is

The diagram below shows equipotential lines in the vicinity of two unequal charges.

Which one of the arrows below best represents the direction of the force that would act on a small positive test charge placed at the point P?

Consider moving the small positive test charge from point P in the situation shown in the diagram to point Q, along three different paths X, Y or Z. Which one of the statements below is correct?

A proton(mass 1 u) and an alpha particle(mass 4u) are accelerated from rest from the positively charged plate X to the negatively charged plate Y.

At the mid-point between the plates, the alpha particle has a velocity v. At this point, the proton has a velocity

The diagram shows an electron, with charge e, mass m, and velocity v, entering a uniform electric field of strength E.

The direction of the field and the electron’s motion are both horizontal and to the right. Which expression gives the distance x through which the electron travels before it stops momentarily?

A positively charged sphere falls vertically in a vacuum between two long parallel plates carrying opposite charges. Which one of the following diagrams best shows the path followed by the sphere?