Download What is the current in the circuit?

Circuits Class Work
1. Looking at Ohm’s Law, fill in the following blanks.
a. As Voltage increases, current _____________.
b. As Voltage decreases, current _____________.
c. As current increases, resistance ____________.
d. As current decreases, resistance ____________.
2. What does your voltage source do?
3. What is current?
4. What does resistance do?
5. If you needed to add resistance to a circuit, would you use a long wire or a thin
wire?
6. If you needed to lower resistance in a circuit would you use a thick wire or a thin
wire?
7. If you wanted maximum current to pass through your current, would you use a
copper wire or a steel wire? Explain.
8. If you wanted to increase current, would you raise the temperature or lower the
temperature?
9. Which of the following does not determine the electrical resistance of a material?
a. Conductivity of a Material
b. Length of wire
c. Temperature
d. Type of insulation surrounding the wire
10. Lower temperature make conductors more resistive.
a. True
b. False
11. If you want to reduce resistance, would you want a thin wire or thick wire?
a. Thin
b. Thick
12. If you want to increase resistance, would you want a long wire or a short wire?
a. Short
b. Long
13. What is the voltage of a circuit with 0.4 amps of current and 15 Ω of resistance?
14. What is the current of a circuit that is hooked up to a 9V battery and a 50 Ω
resistor?
15. What is the resistance of a circuit hooked up to a 6V battery and has a current of
0.2 amps?
16. A diagram of a simple series circuit is shown below. Calculate the amount of
current running through the wire. If a light bulb running through this wire needs
at least 0.2 amps of current to light, will the bulb light if it is attached to this
circuit?
I=
Will the bulb light:
Yes/No
(Circle one)
17. Look at the diagram of the following circuit. Is this a series or parallel circuit? What
is the total resistance running through the circuit? What is the current running through
the whole circuit? What would happen if I unscrewed one light bulb in this circuit?
(Assume each resistor is a light bulb).
18. Look at the following diagram of a circuit. Is this a series or parallel circuit? What is the
current running through each strand? What is the total resistance running through the circuit?
What is the total current running through the circuit? What would happen to the other bulbs if
you unscrewed one light bulb in this circuit? (Assume each resistor is a bulb)
19. Consider a 9-V battery in a circuit with three resistors connected in series.
a.
If the resistance of one of the resistors increases, how will the series
resistance change?
b.
What will happen to the current?
c.
Will there be any change in the battery voltage?
20.
Three 20-Ώ resistors are connected in series across a 120-V generator. What is
the total resistance of the circuit? What is the current in the circuit?
21.
A 10-Ώ resistor, a 15-Ώ resistor, and a 5-Ώ resistor are connected in series
across a 90-V battery. What is the total resistance of the circuit? What is the current in
the circuit?
22.
A string of holiday lights has ten bulbs with equal resistances connected in
series. When the string of lights is connected to a 120-V outlet, the current through the
bulbs is 0.06 A.
a.
What is the total resistance of the circuit?
b.
What is the resistance of each bulb?
23. If the voltage impressed across a circuit is constant but the resistance doubles,
what change occurs in the circuit?
24.
Is electrical resistance greater in a short fat wire or a long thin wire?
25.
A circuit contains a 1.5 volt battery and a bulb with a resistance of 3 ohms.
Calculate the current.
26.
What is the voltage of a circuit with 15 amps of current and a toaster with 8 ohms
of resistance?
27.
How much voltage would be necessary to generate 10 amps of current in a
circuit that has 5 ohms of resistance?
28.
What happens to the current in a circuit if a 1.5 volt battery is removed and is
replaced by a 9 volt battery?
29. What could you do to a circuit consisting of 2 batteries and 2 light bulbs to decrease
the current?
30.
a.
b.
c.
d.
Three 15-Ώ resistors are connected in parallel and placed across a 30-V battery.
Draw a diagram of the scenario.
What is the equivalent resistance of the parallel circuit?
What is the current through the entire circuit?
What is the current through each branch of the circuit?
31. A 120-Ώ resistor, a 60-Ώ resistor, and a 40-Ώ resistor are connected in parallel and placed
across a 12.0-V battery.
a. Draw a diagram of the scenario.
b. What is the equivalent resistance of the parallel circuit?
c. What is the current through the entire circuit?
d. What is the current through each branch of the circuit?
32. Suppose one of the 15.0-Ώ resistors in problem 1 is replaced by a 10.0-Ώ resistor.
a. Draw a diagram of the scenario.
b. Does the equivalent resistance change? If so, how?
c. Does the amount of current through the entire circuit change? In what way?
d. Does the amount of current through the other 15.0-Ώ resistors change? In what way?