How to calculate light intensity?

In summary, light intensity is the amount of light energy that passes through a specific area in a given period of time. It is measured in units of candela (cd) and can be calculated by using the power of the light source and the distance from the light source. Light intensity can be measured using a smartphone, but for accurate measurements, a dedicated light meter is recommended. Light intensity decreases with distance according to the inverse square law, and it is a crucial factor in plant growth as it affects photosynthesis. Providing the right amount of light intensity is important for optimal plant growth.
  • #1
R Sarwar
2
0
I am calculating the light intensity of Mercury.
I was given the average distance from the Sun in AU's which is 0.39.
Using the formula (1/(d^2)), I solved for the light intensity relative to Earth which I found to be 6.57.
I need to find the light intensity in (w/(m^2))
 
Astronomy news on Phys.org
  • #2
You will need some additional input, like the intensity at 1 AU ("solar constant"), or the total power of light emitted by the sun, or something similar.
 

1. How is light intensity defined?

Light intensity, also known as luminous intensity, is the amount of light energy that passes through a specific area in a given period of time. It is measured in units of candela (cd) in the International System of Units (SI).

2. How do I calculate light intensity?

To calculate light intensity, you need to know the power of the light source in watts (W) and the distance from the light source in meters (m). Then, use the formula: light intensity (cd) = power (W) / (4π x distance (m)^2). This will give you the light intensity in candela (cd).

3. Can light intensity be measured using a smartphone?

Yes, it is possible to measure light intensity using a smartphone. There are apps available that use the phone's camera and light sensor to measure the intensity of light. However, for accurate measurements, it is recommended to use a dedicated light meter.

4. Does light intensity decrease with distance?

Yes, light intensity decreases with distance according to the inverse square law. This means that as the distance from the light source increases, the intensity of light decreases exponentially. For example, if you double the distance from the light source, the light intensity will decrease by a factor of four.

5. How does light intensity affect plant growth?

Light intensity is a crucial factor in plant growth as it affects photosynthesis, the process by which plants convert light energy into chemical energy. Too low or too high light intensity can negatively impact plant growth, so it is important to provide the right amount of light for optimal growth.

Similar threads

I Light intensity required to shine a light through an opaque object
    • Electromagnetism
Replies
22
Views
1K
B Distance of Stars / Size of the Universe calculation
    • Astronomy and Astrophysics
Replies
6
Views
2K
How is an autocorrelation function computed? (Dynamic Light Scattering)
    • Electrical Engineering
Replies
1
Views
810
Effect of a polarizer/analyzer on partially polarized light
    • Introductory Physics Homework Help
Replies
25
Views
2K
I Formula For Calculating Field Angle (Beam Angle) of Light?
    • General Math
Replies
2
Views
1K
Procedure to express radiation intensity of an LED in watts/cm^2
    • Electrical Engineering
Replies
6
Views
984
Intensity of Stars and the Inverse Square Law Problem
    • Introductory Physics Homework Help
Replies
10
Views
2K
I Radiant Intensity from Radiant Power and Intensity Distribution
    • Other Physics Topics
Replies
17
Views
3K
Light intensity profile along all radial distances
    • Optics
Replies
4
Views
998
Interference Intensity: Questions & Answers
    • Optics
Replies
7
Views
1K

Hot Threads

Recent Insights

Back
Top