Download Check Your Understanding – Parallel Circuits – KEY (see highlights)

Check Your Understanding – Parallel Circuits – KEY (see
highlights)
1. As more and more resistors are added in parallel to a circuit, the equivalent resistance of the circuit
____________ (increases, decreases) and the total current of the circuit ____________ (increases,
decreases).
2. Three identical light bulbs are connected to a D-cell as shown below. P, Q, X,
Y and Z represent locations along the circuit. Which one of the following
statements is true?
a. The current at Y is greater than the current at Q. Less than
b. The current at Y is greater than the current at P. less than
c. The current at Y is greater than the current at Z. equal
d. The current at P is greater than the current at Q.
e. The current at Q is greater than the current at P. less than
f. The current is the same at all locations. false
3. Three identical light bulbs are connected to a D-cell as shown below. P, Q, X,
Y and Z represent locations along the circuit. At which location(s), if any, will the
current be ...
a. ... the same as at X? P
b. ... the same as at Q? none
c. ... the same as at Y?
Z
d. ... less than at Q? Y & Z
e. ... less than at P? Q & Y & Z
f. ... twice that at Z? Q
g. ... three times that at Y? P & X
4. Which adjustments could be made to the circuit below that would decrease the
current in the cell? List all that apply.
a. Increase the resistance of bulb X. Yes
b. Decrease the resistance of bulb X. No
c. Increase the resistance of bulb Z. Yes
d. Decrease the resistance of bulb Z. No
e. Increase the voltage of the cell (somehow). No
f. Decrease the voltage of the cell (somehow). Yes
g. Remove bulb Y. Yes
5. A 12-V battery , a 12-ohm resistor and a 4-ohm resistor are connected as
shown. The current in the 12-ohm resistor is ____ that in the 4-ohm resistor.
a. 1/3
b. 1/2
c. 2/3
d. the same as
e. 1.5 times
f. twice
g. three times
h. four times
6. A 12-V battery , a 12-ohm resistor and a 4-ohm resistor are connected as
shown. The voltage drop across the 12-ohm resistor is ____ that across the
4-ohm resistor.
a. 1/3
b. 1/2
c. 2/3
d. the same as
e. 1.5 times
f. twice
g. three times
h. four times
ANSWERS CAN BE FOUND AT: http://www.physicsclassroom.com/Class/circuits/u9l4d.cfm