2 Way lightbulb with different power

In summary, a 3-way lightbulb with 2 filaments can produce 50W, 100W, or 150W at a constant voltage of 120V. The connections to the filaments can be made in three ways: parallel, individual, or series. The resistance of each filament for the three wattages can be calculated using the equation P=V^2/R, with the corresponding values being 288ohms, 144ohms, and 96ohms respectively.
  • #1
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Homework Statement


A 3-way lightbulb can produce 50W, 100W or 150W at 120V. Such a bulb contains 2 filaments that can be connected to the 120V individually or in parallel.

a) describe how the connections to the 2 filaments are made to give each of the 3 wattages

b) What can be the resistance of each filament?

The Attempt at a Solution



I'm really not sure where to start :confused:
 
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  • #2
equation: P=VI=V^2/R
obviously, for two filaments (ie. two resistances), you can make the following combo (if R1=R2)

1. R1//R2 (parallel)
2. R1 (by itself) or R2 (by itself)
3. R1+R2 (series)

with effective resistance of case 1 < case 2 < case 3

you got it now?

now if case 3 (in series is not allowed then) you will have to assume that R1 not equal to R2 to get three cases
 
  • #3
Ok, so using P=V^2/R

For the 50w wattage, V is constant at 120V, P=50W.
Subbing into the equation, R=288ohms

For the 100W wattage, subbing into the equation, R=144ohms

For the 150W wattage, subbing into the equation, R=96ohms

but how do I know if they are connected individually or in parallel?
I'm a massive physics noob, go easy on me!
 

What is a 2-way lightbulb with different power?

A 2-way lightbulb with different power is a type of lightbulb that has two distinct levels of brightness that can be controlled by a switch. This means that the lightbulb can be used for both general and task lighting, providing versatility and energy efficiency.

How does a 2-way lightbulb with different power work?

A 2-way lightbulb with different power works by having two separate filaments inside the bulb. These filaments have different wattage ratings, allowing for different levels of brightness. The switch on the lightbulb controls which filament is activated, resulting in either a lower or higher level of brightness.

What are the benefits of using a 2-way lightbulb with different power?

There are several benefits to using a 2-way lightbulb with different power. These include energy efficiency, as you can choose the appropriate level of brightness for your needs, and versatility, as the lightbulb can be used for both general and task lighting. Additionally, these lightbulbs tend to have a longer lifespan compared to traditional single-level lightbulbs.

How do I install a 2-way lightbulb with different power?

The installation process for a 2-way lightbulb with different power is the same as installing a traditional single-level lightbulb. Simply screw the bulb into the light fixture and make sure it is securely in place. Make sure to turn off the power to the light fixture before installation to avoid any accidents.

Can I use a 2-way lightbulb with different power in any light fixture?

Generally, 2-way lightbulbs with different power can be used in most standard light fixtures. However, it is important to check the wattage and voltage ratings of the light fixture to ensure compatibility. Using a lightbulb with a higher wattage than what the fixture is rated for can cause damage and be a fire hazard.

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