Posted by **Tiffini** on Sunday, November 14, 2010 at 11:53pm.

3. You have a simple circuit with a light bulb (R = 50 Ω) and a power supply (you can treat it like a battery with 120 V). Unfortunately, a loose screw fell on the circuit and is connected in parallel to the light bulb. You can treat the screw as a resistor with a resistance of 1 Ω.

a. Sketch this circuit

b. What effect does the screw have on the circuit? Focus on the current and voltage.

c. This situation is also known as a “short circuit.” Why is this bad if it happens at home?

- Physics -
**Henry**, Wednesday, November 17, 2010 at 8:40pm
a. If the 12ov supply holds up, you have a parallel circuit with a 1 ohm and a 50 ohm resistor in parallel.

b. The current drawn by the lamp:

I = V / R = 120 / 50 = 2.4 Amps.

The current drawn by the 1 ohm resistor:

I = V / R = 120 / I = 120 Amps.

The total current:

I(tot) = 2.4 + 120 = 122.4 Amps.

These calculations were based on the assumption that the 120v supply remained constant This is unlikely

unless the current rating of the power supply is well over 120 Amps. A 1 ohm

resistor connected across a 120v 5 Amp

supply would definitely be a short circuit. But if it is connected across a 120v 100 Amp supply; it would be an overload but not a short circuit.

c. A short circuit can trip a circuit breaker, blow a fuse, or burn the house down.

## Answer this Question

## Related Questions

physics - What is the minimal resistance of a 100 W light bulb designed to be ...

physics - A light bulb is wired in series with a 133-Ω resistor, and they ...

physics - You are in the lab with a 10 V battery. You have a 10 W light bulb and...

college physics - You are in the lab with a 10 V battery. You have a 10 W light ...

Physics - Multiple-Concept Example 9 reviews the concepts that are important to ...

Physical Science - 1.Nico uses wire to connect a battery, light bulb, and a ...

Physics - One 10.0 Ω resistor is wired in series with 10.0 Ω resistors...

physics - Light bulb packages will have at least two numbers on them; a power ...

Physics - Suppose that the light bulb in the figure is a 61.8-W bulb with a ...

physics 102 - three lamps connected to a 120-V AC (rms) household supply ...