Given four electric charges placed at the corners of a rectangle 5cm wide and 4cm tall, such that two charges at the top corners are+2Q while the charges at the lower corners are-3Q each. Calculate the magnitude and direction of the electric field at the centre of the rectangle. If a charge -5Q is placed at the centre of the rectangle, state the law that governs the force between the charge at the centre and one of the +2Q charges. What is the magnitude and type of the force between the-5Q charge and one of the +2Q charges?
Answers
Answer:
The given figure shows a square of side 10 cm with four charges placed at its corners. O is the centre of the square.
Where,
(Sides) AB=BC=CD=AD=10cm
(Diagonals) AC=BD=10
2
cm
AO=OC=DO=OB=5
2
cm
A charge of amount 1μC is placed at point O.
Force of repulsion between charges placed at corner A and centre O is equal in magnitude but opposite in direction relative to the force of repulsion between the charges placed at corner C and centre O. Hence, they will cancel each other. Similarly, force of attraction between charges placed at corner B and centre O is equal in magnitude but opposite in direction relative to the force of attraction between the charges placed at corner D and centre O. Hence, they will also cancel each other. Therefore, net force caused by the four charges placed at the corner of the square on 1μC charge at centre O is zero.
solution