emags

The potential field (voltage) at a certain point A due to a point charge that is located at another point B is ___ to  the permittivity of the material in between.

• Independent

• Directly proportional

• Inversely proportional

• None of the above

 If the voltage at point A with respect to a reference point X is VA and the voltage at point B with respect to a  reference point X is VB, the potential difference VBA is equal to

• VB − VA

• VA + VB

• VA − VB

• both b and c

The capacitance per unit length of a coaxial __ if the dielectric material’s permittivity decreases.

• Increases

• Decreases

• Remains the same

• Cannot be determined. Not enough data.

The unit for material’s conductivity(σ).

• S ∙ m

• S⁄m

• m⁄Ω

• Ω ∙ m

Measures the amount of electric charge stored for a given electric potential.

• Electric field intensity

• Voltage

• Capacitance

• Current density

Which of the following equations defines the relation between electric field and voltage.

• E = −(∇ ∙ V)

• E = −(∇ × V)

• E = −∇ ∙ (∇ × V)

• E = −∇V

 A capacitor can store 1 milli-joule at a potential difference of 5 V on its terminal leads when fully charge.  Determine the capacitance.

• 40 μF

• 400 μF

• 80 μF

• 200 μF

The following statements is correct about electric dipole except for

• Two point charges that are either both positive charge, or both negative charge.

• Two point charges that are either both positive charge, or both negative charge.

• The following statements is correct about electric dipole except for

• None of the above

What will happen to the capacitance (C) of a capacitor if the external electric field decreases?

• Decreases

• Increases

• Remains the same

• Cannot be determined. Not enough information

An induced electric field within a dielectric material due to the external application of an electric field E is called ___. This electric field is generally weaker and opposite in direction to the applied E.

• Dipole field

• Dielectric field

• Counter field

• Polarization field