CASTLE Unit 6
Worksheet 1 – Potential Differences and
Voltmeters in Circuits
Name_______________________________
Date__________________Period________
1. Based on your experiments, how do you know a voltmeter is a device that can be utilized to measure
pressure differences? What units are used for measuring electric pressure? What term do the ‘experts’
use for electric pressure?
2. What would happen if you connected a voltmeter in series with a circuit component? Why is this not
appropriate for good measurements?
3. A good measuring device does not significantly interfere with the circuit being measured. In terms of
being a good measuring device describe:
a) Whether the resistance of the voltmeter is high or low.
b) How should the voltmeter be connected in the circuit in relation to where you want to know the
electric pressure difference?
c) Why does the voltmeter needs to have the resistance it does in order to be a good measuring device?
4. You have three bulbs connected in series. The voltage drop across each bulb is 2.0 Volts. Are the bulbs
identical? How do you know? What is the voltage across the battery?
5. You have four bulbs connected in series. The voltage drop across the battery is 12 Volts. The voltage
drop across bulb A is equal to 1 Volt, the drop across bulb B is 5 volts, the drop across bulb C is equal to
4 volts.
What is the voltage drop across bulb D?
Which bulb has the greatest resistance?
Which bulb has the smallest resistance?
6. You have five bulbs connected in parallel. The voltage drop across the first branch is 10 Volts. What is
the voltage drop across the battery? What is the voltage drop across the other branches
©Modeling Workshop Project 2006
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C6 WS 1 v3.2-Rice 06
7. Complete the circuit below with the correct pressure difference values for each component by recording
them in the spaces provided. Note that the voltmeter placed across the battery shows a value of 6.Volts.
L aV
6V
Lb
L
.
V
b
V
V.
c
.
R
d
R
e
V.
V.
8. Look at the circuit below. Color code the circuit and determine the voltage values across each bulb and
the battery as closely as you can. You may assume that each cell in the battery has a pressure difference
of 4V.
©Modeling Workshop Project 2006
2
C6 WS 1 v3.2-Rice 06