physics quiz

A repelling force occurs between two charged objects when the charges are of

•   

  equal magnitude.

   

•   

  unlike signs.

   

•   

  like signs.

   

•   

  unequal magnitude.

   

The figure shown above demonstrates charging by

• contact

• polarization

• induction

• grounding

In the diagram shown above, the circles represent small balls that have electric charges. Ball 1 has a negative charge, and ball 2 is repelled by ball 1. Next, you see that ball 2 repels ball 3 and that ball 3 attracts ball 4. What is the electric charge on ball 4?

•   

  Ball 4 has a negative charge.

   

•   

  It is not possible to determine the charge on ball 4.

   

•   

  Ball 4 may have either a positive or negative charge.

   

•   

  Ball 4 has a positive charge.

   

Electric charge is

•   

  found only in a conductor.

   

•   

  found only in insulators.

   

•   

  conserved.

   

•   

  not conserved.

   

Charge is most easily transferred in

• insulators

• conductors

• semiconductors

• nonconductors

Which is the most correct statement regarding the drawing of electric field lines?

•   

  Electric field lines can start on a charge of either polarity.

   

•   

  Electric field lines always connect from one charge to another.

   

•   

  Electric field lines always form closed loops.

   

•   

  Electric field lines never cross each other.

   

If a positively charged glass rod is used to charge a metal bar by induction, the charge on the bar

•   

  must be negative.

   

•   

  must be positive.

   

•   

  will be greater in magnitude than the charge on the glass rod.

   

•   

  will be equal in magnitude to the charge on the glass rod.

   

What happens when a rubber rod is rubbed with a piece of fur, giving it a negative charge?

•   

  Electrons are added to the rod.

   

•   

  The fur is left neutral.

   

•   

  Electrons are added to the fur.

   

•   

  Protons are removed from the rod.

   

Which sentence best describes electrical conductors?

•   

  Electrical conductors have high tensile strength.

   

•   

  Electrical conductors have low mass density.

   

•   

  Electrical conductors have electric charges that move freely.

   

•   

  Electrical conductors are poor heat conductors.

   

If the charge is tripled for two identical charges maintained at a constant separation, the electric force between them will be changed by what factor?

• 2/3

• 1/9

• 9

• 19