What is the average intensity at a distance?

In summary, the average intensity of a 60 W bulb at a distance of 0.40 m is determined by the equation I = P/A, where A is the surface area of a sphere with a radius equal to the distance from the bulb.
  • #1
Sylvia
30
1

Homework Statement


A 60 W bulb radiates light uniformly in all directions. What is the average intensity of the light bulb at a distance 0.40 m.

Homework Equations


I = P/A, part of my problem is that I don't know the relevant equations

The Attempt at a Solution

 
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  • #2
Your equation is correct.
You have to assume that the bulb radiates uniformly in all directions, then the area ##A## over which the power is distributed is the surface of a sphere with radius the distance you have.
 
  • #3
Thank you, that makes so much sense. I thought the area had to be of the object radiating the light.
 

Related to What is the average intensity at a distance?

What is the average intensity at a distance?

The average intensity at a distance refers to the amount of energy or force per unit area that is transmitted through a specific distance. It is commonly used in physics and engineering to measure the strength or magnitude of a wave or field at a given distance.

How is the average intensity at a distance calculated?

The average intensity at a distance is calculated by dividing the total energy or force of a wave or field by the area it covers at that distance. This can also be calculated by measuring the amplitude or magnitude of the wave or field and applying the appropriate formula.

What factors can affect the average intensity at a distance?

The average intensity at a distance can be affected by various factors such as the source of the wave or field, the distance from the source, the medium through which the wave or field travels, and any obstructions or obstacles in its path. Additionally, the wavelength and frequency of the wave or field can also impact its intensity.

Why is it important to measure the average intensity at a distance?

Measuring the average intensity at a distance is important in understanding the strength and behavior of waves and fields. It can also be used to determine the potential impact or danger of certain sources, such as radiation or sound waves, and to ensure proper safety measures are in place.

What are some common units of measurement for average intensity at a distance?

The most common units of measurement for average intensity at a distance are watts per square meter (W/m²) for electromagnetic radiation, pascals (Pa) for sound waves, and newtons per square meter (N/m²) for mechanical waves. Other units, such as decibels (dB), are also used for specific types of waves or fields.

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