Grade 12 Physics Revision Quiz

If we have 2 charges, q1 and q2, that are 50cm apart, what is the magnitude of the force exerted on q1 by q2if we know that q1 has a charge of 10μC and q2 has a charge of −20μC?

• 2.7N

• 7.2N

• 6.3N

• 3.6N

If we have 2 charges, q1 and q2, that are 14cm apart, what is the force exerted on q1 by q2 if we know that q1 has a charge of −13μC and q2 has a charge of −12μC?

• 67.31N

• 52.86N

• 71.63N

• 143.16N

A positively charged sphere is brought near one end of an uncharged metal bar. The ends A and B of the metal bar will be charged:

• (A) positive, negative

• (B) negative, positive

• (C) positive, positive

• (D) negative, negative

Sphere A carries a net positive charge, and sphere B is neutral. They are placed near each other on an insulated table. Sphere B is briefly touched with a wire that is grounded. Which statement is correct?

• (A) sphere B remains neutral

• (B) sphere B is now positively charged

• (C) sphere B is now negatively charged

• (D) sphere B is now positive, and sphere A is negative

Three-point charges lie at the vertices of an equilateral triangle as shown. All three charges have the same magnitude, but charges #1 and #2 are positive (+q) and charge #3 is negative (–q). The net electric force that charges #2 and #3 exert on charge #1 is in

• the +x-direction.

• the –x-direction.

• the +y-direction.

• the –y-direction.

• none of the above.

Three-point charges lie at the vertices of an equilateral triangle as shown. All three charges have the same magnitude but charge #1 is positive (+q) and charges #2 and #3 are negative (–q). The net electric force that charges #2 and #3 exert on charge #1 is in

• the +x-direction.

• the –x-direction.

• the +y-direction.

• the –y-direction.

• none of the above.

A positive point charge +Q is released from rest in an electric field. At any later time, the velocity of the point charge

• is in the direction of the electric field at the position of the point charge.

• is directly opposite the direction of the electric field at the position of the point charge.

• is perpendicular to the direction of the electric field at the position of the point charge.

• is zero.

• Not enough information is given to decide.

Two-point charges and a point P lie at the vertices of an equilateral triangle as shown. Both point charges have the same magnitude q but opposite signs. There is nothing at point P. The net electric field that charges #1 and #2 produce at point P is in

• the +x-direction.

• the –x-direction.

• the +y-direction.

• the –y-direction.

• none of the above.

Positive charge is uniformly distributed around a semicircle. The electric field that this charge produces at the centre of curvature P is in

• the +x-direction.

• the –x-direction.

• the +y-direction.

• the –y-direction.

• none of the above.

Rank the following electric fields in order of their magnitude, from largest to smallest.

• ABCD

• BCAD

• DCAB

• DCBA