# Manufacturer of a 12V car headlight

• al8719
In summary, the conversation discusses the use of an ammeter to measure the current of a 12V car headlight, which is specified to draw 6A. The ammeter has a resistance of 0.1 Ohms and is designed to measure currents up to 10A. The first figure shows a current reading of 5.71A and the second figure would likely have a current reading of 0A or a high current of approximately 120A, causing the fuse to blow. The use of Kirchoff's Voltage Law and Ohm's Law are suggested to accurately calculate the current in figure b.
al8719

## Homework Statement

The manufacturer of a 12V car headlight specifies it will draw a current of 6A. You would like to check this claim with an ammeter designed to measure currents up to 10A and having a resistance of 0.1 Ohms.

http://img168.imageshack.us/img168/7831/oaammeterqk3.th.png
What is the current readings in (A) of figure a) and b)

I=V/R

## The Attempt at a Solution

So I think a has a value of 5.71 because 12/(2+.1)...is this wrong...and would figure b) be 0 since the fuse would blow? I'm basically lost.

Last edited by a moderator:
I think you are right on both. Why do you think you are lost?

You did the first part right, which would give the current through the circuit for the ammeter and the headlight (if the manufacturer is right).

In the second part the fuse will probably blow, the current would approximately be 120A, which gives a lot of power. Regardless of whether the fuse flows or not, you ought to figure out the current through there, don't just use my approximation. You can use Kirchoff's Voltage Law or Current Law, or both, with Ohm's law.

## 1. What is the typical lifespan of a 12V car headlight?

The average lifespan of a 12V car headlight is around 500-1000 hours, but this can vary depending on the specific brand and usage.

## 2. How do I know if a 12V car headlight is compatible with my vehicle?

Before purchasing a 12V car headlight, it is important to check your vehicle's manual or consult with a mechanic to ensure compatibility. Different vehicles may require different sizes or types of headlight bulbs.

## 3. Can I replace a 12V car headlight on my own?

Yes, replacing a 12V car headlight is a relatively simple task. However, it is important to follow the proper safety precautions and consult your vehicle's manual for specific instructions.

LED headlights are generally considered to be more energy efficient and have a longer lifespan compared to halogen headlights. However, they may be more expensive upfront.

## 5. What is the purpose of a 12V car headlight relay?

A 12V car headlight relay is an electrical switch that allows a low current from the headlight switch to control a higher current to the headlight bulbs. This helps to protect the headlight switch from damage and ensures a consistent power supply to the headlights.

• Introductory Physics Homework Help
Replies
4
Views
328
• Introductory Physics Homework Help
Replies
4
Views
3K
• Introductory Physics Homework Help
Replies
2
Views
2K
• Introductory Physics Homework Help
Replies
5
Views
1K
• Introductory Physics Homework Help
Replies
2
Views
4K
• Introductory Physics Homework Help
Replies
2
Views
7K
• Introductory Physics Homework Help
Replies
34
Views
4K
• Introductory Physics Homework Help
Replies
17
Views
3K
• Introductory Physics Homework Help
Replies
3
Views
4K
• Introductory Physics Homework Help
Replies
27
Views
3K