Steradian

High school (ages 12+)
Mathematics & Numbers

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/steradian

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the SI unit classification?Derived unit for solid angle measurement
2. What is the total solid angle?A complete sphere subtends a solid angle of 4π steradians
3. How do we find the solid angle in steradians?Take the surface area of the part of a sphere that the object covers and divide it by the square of the sphere’s radius. That number is the solid angle in steradians.
4. Who invented the steradian?The German scientist Jacob B. Listing first named the steradian in 1878. It later became part of the SI system of units.

Solid Angle: A measure of the extent of a three-dimensional region or object as viewed from a point.
Radiant Intensity: The power emitted by a source per unit solid angle, measured in watts per steradian (W⋅sr⁻¹).
SI Derived Unit: A unit formed by combining base SI units, such as the steradian for solid angles.