Three point charges are located at the corners of an equilateral triangle of side 0.20 m
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Three point charges are located at the corners of an equilateral triangle of side 0.20 m. Two of the charges are +5.0 µC each and are at vertices A and B; the third charge at vertex C is −3.0 µC.
(i) Draw a labelled diagram showing the direction of the force exerted on the charge at vertex C by each of the other two charges.
(ii) Calculate the magnitude and direction of the resultant force on the charge at C. Give the angle the resultant makes with side CA.
(iii) Keeping the magnitudes unchanged, the charge at vertex B is now reversed in sign. Without repeating the full calculation, determine qualitatively whether the magnitude of the resultant force on C will increase, decrease or remain the same, and indicate the new direction relative to side CA. Justify your answer.