Practice problems

Assume ideal batteries, treat light bulbs as ohmic devices, assume all light bulbs are identical.

1. What happens to the other bulbs if you unscrew bulb D?



A. They all go out

B. They all get dimmer

C. They all get brighter

D. A and B get dimmer, C gets brighter

E. A and B get brighter, C gets dimmer



2. Find the potential drop across R₂.





3. Find the ratio I₃/I₄.





4. Write three loop equations and four junction equations that could be used to solve this circuit (find currents and voltage drops across resistors).





5. Rank the bulbs from brightest to dimmest.



A. A = B > C = D

B. A = B < C = D

C. A = B > C > D

D. B > A > C = D

E. A = C = B = D



6. Rank the bulbs from brightest to dimmest.



A. A = B > C = D = E

B. A = B < C = D = E

C. A = B = E > C > D

D. A = B = E > C = D

E. A > B > C = D = E



7. Which resistor has the highest voltage drop?



A. top left

B. top right

C. bottom left

D. bottom right

E. bottom left and bottom right tie for the highest voltage drop

F. all 3-ohm resistors tie for the highest voltage drop



8. Which direction does the current flow between a and b?



A. from a to b

B. from b to a

C. there is no current flowing




8. Rank the bulbs from brightest to dimmest.



A. A = B > C = D = E

B. A > B > C = D > E

C. B > A > E > C = D

D. B > A = E > C = D

E. A = E > B > C = D



9. Find the voltage drop across R₁.