Understanding the Brightness of Light Globes in Series Circuits

In summary, when only Sa is switched on, the total resistance of the circuit remains the same and the current in each lamp decreases because it is split into two parallel circuits. When only Sb is switched on, one bulb is short circuited and all the current passes through Sb, turning the bulb off.
  • #1
TyErd
299
0

Homework Statement


1. Describe and explain how the brightness of each globe will be affected if only Sa is switched on.
2. Describe and explain the effects of the light globes if only Sb is switched on.


Homework Equations


None


The Attempt at a Solution


No working out required I believe.
 

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  • #2
If only Sa is closed, what happens to the total resistance of the circuit?
What is the current in each lamp?
If Sb is closed, What change in the resistance you observe in the circuit?
 
  • #3
for when Sa is closed,the total resistance doesn't change because their was current flowing through the globes but from a different path, current in each lamp would decrease because it is being split up now that there is an extra path?
 
  • #4
TyErd said:
for when Sa is closed,the total resistance doesn't change because their was current flowing through the globes but from a different path, current in each lamp would decrease because it is being split up now that there is an extra path?
It is not correct. Since the total resistance remains the same, the current drawn from the cell is the same. In both the cases , it equally branches out in two parallel circuits. So in each the branch the current is I/2.
 
  • #5
Okay, i understand, now for when only Sb is closed,...im not really sure
 
  • #6
TyErd said:
Okay, i understand, now for when only Sb is closed,...im not really sure
One bulb is short circuited. Leaving that bulb, calculated the total resistance and the current in each bulb.
 
  • #7
why is it short circuited?
 
  • #8
TyErd said:
why is it short circuited?
All the current passes through the Sb. So the bulb will be off.
 
  • #9
does all current pass through Sb or does it divide into two paths?
 

1. How do light globes work in circuits?

Light globes work by using the flow of electricity to heat up a thin wire called a filament. As the filament heats up, it emits light. The electricity flows through the filament because it is made of a material that allows electrons to move easily. This creates a closed circuit, allowing the electricity to flow continuously and the light globe to stay lit.

2. What is the purpose of a light globe in a circuit?

The purpose of a light globe in a circuit is to convert electrical energy into light energy. It is often used as a source of light in homes, streetlights, and other electronic devices.

3. How are light globes connected in a circuit?

Light globes are typically connected in a parallel circuit, where each light globe has its own separate path to the power source. This allows each light globe to receive the same amount of voltage and stay lit even if one light globe burns out.

4. How does the brightness of a light globe in a circuit change?

The brightness of a light globe in a circuit can change depending on the amount of voltage and current flowing through the circuit. Increasing the voltage or current will make the light globe brighter, while decreasing the voltage or current will make it dimmer.

5. Why do light globes sometimes burn out in circuits?

Light globes can burn out in circuits due to various reasons such as high voltage, high current, or a damaged filament. When the filament gets too hot, it can break or melt, causing the light globe to stop working. It's important to use the correct voltage and current for the light globe to prevent it from burning out prematurely.

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