Download lab 14a directions

Lab 14A
series vs. parallel
and short circuits
Set up your circuit board as shown above
Record the voltage drops at the above points and answer the
questions below:
1) What relationship is there among the four voltage drops
you measured?
2) Is AD the same as the voltage across the batteries? What
percent difference is there (if any)?
3) Compare the sum of AB, BC, and CD with AD. What
percentage difference is there? Explain why there is a
difference. Explain the difference in #2 if there was one.
Measure the current for the three circuits above.
Answer the following questions:
1. What happens to the current as more bulbs
are added? Explain using Ohm’s Law
2. What happens to the other two bulbs when
one bulb is unscrewed? Explain why.
Add a short circuit (wire) that bypasses two
bulbs and measure the current before and
after.
Answer the following questions:
1. Use Ohm’s Law and the concept of
resistance to explain the change in current.
2. How does the current in a one-bulb circuit
compare with the current through this short
circuited circuit?
3. How does the resistance of a wire compare
with the resistance of a bulb?
4. Directly measure the resistance of a wire
(set multimeter to 200 Ω)
5. Why are short circuits dangerous?
Build the following parallel circuit.
Measure the following and answer the questions:
1. Compare brightness of 3 bulbs in series vs. 3 bulbs in
parallel.
2. Unscrew one bulb. What happens to the others?
Explain the difference between this result and the one
you got in series.
3. Would you want a string of holiday lights wired in
series or parallel? Why?