Question 13 (Solutions on page
point by light, inextensible strings of equal length, making an angle of 20° with each other
Two positively charged metal spheres each with a mass of 4 g are suspended from the same
contact and are then released. Once released they now make a new angle, 0, with
each other,
as shown in the diagram 1 below. The spheres are then forced together until they make
20°
P
+2μC
(R
+18μC
Diagram 1
CO
0
Diagram 2
(4)
(2)
(3)
(4)
(4
(2
13.1 Sketch the combined field pattern between charges P and R in diagram 1.
13.2 State Coulomb's Law.
13.3 Draw a labelled free body diagram of the forces acting on sphere R in
diagram 1.
13.4 Calculate the magnitude of the electrostatic force of repulsion between the
charges in diagram 1.
13.5 Hence, calculate the distance between the charges in diagram 1.
13.6 Calculate the new charge on each sphere after touching in diagram 2.
13.7 Were electrons transferred From P to R or R to P when they touch?
13.8 How many electrons were transferred when P and R touch?
13.9 Determine the value of 0, the new angle in diagram 2 if the spheres are now
8,66m apart.