In the figure below, positive charges q2 and q3 exert on charge q1 a net electri
ID: 1562208 • Letter: I
Question
In the figure below, positive charges q2 and q3 exert on charge q1 a net electric force that points along the +x axis. If a positive charge Q is added at (b, 0), what now will happen to the force on q1? (All charges are fixed at their locations.) (a) No change in the size of the net force since Q is on the x-axis. (b) The size of the net force will change but not the direction. (c) The net force will decrease and the direction may charge because of the interaction between Q and the positive charges q2 and q3. (d) The net force will increase and the direction may charge because of the interaction between Q and the positive charges q2 and q3. (e) Cannot determine without knowing the magnitude of q1 and/or Q. In the figure below, the electric field at point P is directed upward along the y-axis. If a negative charge -Q is added at a point on the positive y-axis, what happens to the field at P? (All of the charges are fixed in position.) (a) Nothing since -Q in on the y-axis. (b) Strength will increase because -Q is negative. (c) Strength will decrease and direction may change because of the interaction between -Q and the two negative q's. (d) Strength will increase and direction may change because of the interaction between -Q and the two negative q's. (e) Cannot determine without the forces -Q exerts on the two negative q's.Explanation / Answer
Q No 1
The correct answer is (b)
The Q charge exerts a force on q1 in the x direction. And we are given that the net force due to q2 and q3 is already in x direction. Hence the net force will still be in x direction but its magnitude will be different.
Q No 2
The correct answer is (b)
The electric field due to -Q charge will be in +y direction ( the direction of electric field is the direction of force on a positive charge). We are given that the field due to -q is already in +y direction. Hence the net field will increase and point in +y direction,