Electric Charges & fields

The surface considered for Gauss’s law is called

• (a) Closed surface

• (b) Spherical surface

• (c) Gaussian surface

• (d) Plane surface

• Yes

• No

A mass m=20g has a charge q=3.0mC . It moves with a velocity of 20m/s and enters a region of electric field of 80N/C in the same direction as the velocity of the mass. The velocity of the mass after 3 seconds in this region is

• 80 m/s

• 56m/s

• 44m/s

• 40m/s

Q_A and Q_B are two charges creating an electric field. Based on the diagram, what can we say about the strength electric fields coming from Q_A and Q_B

The diagram above shows a point, P, located midway between two oppositely charged parallel plates.

If an electron is introduced at point P, the electron will

• accelerate toward the negatively charged plate

• travel at constant speed toward the negatively charged plate

• travel at constant speed toward the positively charged plate

• accelerate toward the positively charged plate

• 5.6 x 10⁸ Vm

• 1.4 x 10⁸ Vm

• 22.4 x 10⁸ Vm

• 1.1 x 10⁸ Vm

Identical charges A, B, and C are located between two oppositely charged parallel plates, as shown in the diagram below. The magnitude of the force exerted on the charges by the electric field between the plates is

• least on A and greatest on C

• the same on A and C, but less on B

• the same for A, B, and C

• greatest on A and least on C

A region surrounding a stationary electric dipoles has

• Magnetic field only

• Electric field only

• Both electric and magnetic fields

• No electric and magnetic fields

The given diagram shows charges of +2 µC and -2 µC situated at points P and Q respectively. Point X is midway between P and Q.

What is the direction of the electric field and the value of the electric potential at point X?

• A

• B

• C

• D

Consider the points lying on a straight line joining two fixed opposite charges. Between the charges there is

• No point where electric field is zero

• Only one point where electric field is zero

• No point where potential is zero

• Only one point where potential is zero