Science Bowl Practice Questions

Physics - 7

40.

Multiple Choice: Five coulombs of charge are placed on a thin-walled conducting shell. Once the
charge has come to rest, the electric potential inside the hollow conducting shell is found to be:

w) zero
x) uniform inside the sphere and equal to the electric potential on the surface of the sphere
y) smaller than the electric potential outside the sphere
z) varying as one over r squared.

ANSWER: X -- UNIFORM INSIDE THE SPHERE AND EQUAL TO THE ELECTRIC OTENT

41.

Short Answer: A two farad and a four farad capacitor are connected in series. What single capacitance
is "equivalent" to this combination?

ANSWER: 4/3 FARADS

42.

Multiple Choice: Three capacitors with different capacitances are connected in series. Which of the
following statements is TRUE?

w) All three of the capacitors have the same potential difference between their plates.
x) The magnitude of the charge is the same on all of the capacitor plates.
y) The capacitance of the system depends on the voltage applied across the three
capacitors.

ANSWER: X -- THE MAGNITUDE OF THE CHARGE IS THE SAME ON ALL OF
THE CAPACITOR PLATES

43.

Multiple Choice: For a parallel-plate capacitor with plate area "A" and plate separation "d", the
capacitance is proportional to which of the following?

w) A divided by d squared
x) A times d
y) A divided by d
z) d divided by A

ANSWER: Y -- A DIVIDED BY D

44.

Multiple Choice: A constant potential difference is applied across the plates of a parallel-plate
capacitor. Neglecting any edge effects, the electric field inside the capacitor is:

w) constant
x) varying as one over r squared
y) decreasing as one moves from the positive to the negative plate z) zero

ANSWER: W -- CONSTANT

45.

Short Answer: A 10 farad capacitor is used in a circuit. The voltage difference between the plates of
the capacitor is 20 volts. What is the magnitude of the charge on each of the capacitor's plates?

ANSWER: 200 COULOMBS

46.

Short Answer: A circuit which employs a DIRECT CURRENT source has a branch which contains a
capacitor. After the circuit has reached a steady state, what is the magnitude of the current in the circuit
branch which contains the capacitor?

ANSWER: THE CURRENT IS ZERO

47.

Short Answer: A charged particle is moving in a UNIFORM magnetic field. If the direction of motion
of the charged particle is parallel to the magnetic field, describe the shape of the charged particle's path.

ANSWER: STRAIGHT LINE