trial

Electric field intensity is a ............

• base quantity

• scaler quantity

• non vector quantity

• vector quantity

The spacing between field lines shows their

• direction

• position

• strength

• none of above

The region around a charge q in which it exerts a force on a test charge is called

• electric field intensity

• electric force

• electric field

• coulomb's force

The field lines always emerge from

• negative charge

• positive charge

• the central point of both charges

• all of above

Two point charges, q1 and q2, are placed a distance r apart. The electric field is zero at a point P between the charges on the line segment connecting them. We conclude that:

• q1 and q2 must have the same magnitude and sign P must be midway between q1 and q2

• q1 and q2 must have the same sign but may have different magnitudes

• q1 and q2 must have equal magnitudes and opposite signs

• q1 and q2 must have opposite signs and may have different magnitudes

Charges Q, -Q, and q are placed at the vertices of an equilateral triangle as shown. The total force exerted on the charge q is:

• toward charge Q.

• toward charge -Q.

• away from charge Q.

• left

• right.

In the figure, if Q = 30 µC, q = 5.0 µC, and d = 30 cm, what is the magnitude of the electrostatic force on q?

• 15 N

• 23 N

• zero

• 7.5 N

• 38 N

If a = 60 cm, b = 80 cm, Q = –6.0 nC, and q = 4.0 nC, what is the magnitude of the electric field at point P?

• 35 N/C

• 42 N/C

• 52 N/C

• 64 N/C

• 104 N/C

Two small charged objects repel each other with a force F when separated by a distance d. If the charge on each object is reduced to one-fourth (1/4) of its original value and the distance between is reduced to d/2, the force becomes:

• F/16

• F/8

• F/4

• F/2

• F

A particle (mass = 4.0 g, charge = 80 mC) moves in a region of space where the electric field is uniform and is given by Ex = –2.5 N/C, Ey = Ez = 0. If the velocity of the particle at t = 0 is given by vx = 80 m/s, vy = vz = 0, what is the speed of the particle at t = 2.0 s?

• 40 m/s

• 20 m/s

• 60 m/s

• 80 m/s

• 180 m/s