What is 1 Steradian? Basic S I Unit of Solid Angle. How to construct a 1 Steradian Solid Angle?
Class 9 Physics
Class 9 Math
Class 9 chapter 1 units and measurements
S i unit of Solid Angle
Class ten maths
Class 10 Physics
CBSE CLASS 10 Mathematics
Cbse class 10 physics
Class10 physics ssc class 10
Physics class 10
ICSE CLASS 10 STANDARD
ICSE CLASS 9 Physics
Rbse Class10 physics
MPBSE CLASS 10 MATH
UPMBSE class 10 physics
What is 1 steradian?
Steradian is a unit of solid angle, in S, I, Method.
TO realize what it is. And how bigger it is. Let us consider a sphere. Its Radius may be of any size, of your imagination. Let its value be, r.
Therefore, its surface area should be, 4 pi r Square. Or, 12.56 r Square. After putting value of pi. Which is approximately 3.14.
Now, take a portion of the surface area, of size, r Square.
It may be of any shape. But its area should be, r Square.
Curve it about the sphere. Connect its edges, to the center of the sphere.
Now, you can see the solid angle. Which looks like a spotlight. Whose lamp, appear to be at the center of the sphere.
This solid angle is called, a one steradian angle.
If you take another portion of spherical surface, of area, 2 r Square. Then it will form, a 2 steradian size solid angle.
More you increase the surface area, larger the angle you should get from it.
Thus, we understand that, ratio of surface area, to the Square of its radius, is called, a solid angle.
For an hemisphere, the solid angle, it creates at its center, is of, 2 pi steradian.
For the whole sphere, the solid angle is, 4 pi steradian.
Steradian is a zero dimensional unit. It is expressed in, s r. And denoted in, greek alphabet, omega.
Note that, there is a non s i unit, of solid angle. It is called, sq degree, or degree Square. And symbolizes with, deg Square. And, denoted in, bracket degree Square.
1 degree Square is equal to, pi by 180 whole Square, steradian. Or, 3.0462 into 10 to the power minus 4, steradian. Alternately, we can say that, 1steradian is equivalent to, 3283 Square degree.
The Sun, or the moon, creates almost equal solid angle, on the surface of the earth. It is roughly, 6.807 into 10 to the power minus 5, steradian. Which is about a portion of, 0 point zero zero zero five four two percent, of the total viewable sky.
Both two human eyes, collectively can see a view of 200 degree along the horizontal plane. And, 135 degree along the vertical plane. Therefore, total viewing portion is, about 4.17 steradians. Or, 13700 Square degree. Thus, an average human can see only, 33.2 percent of the total viewable scene, at a single glance. Although, it depends on the anatomy of a person's face.
Hope you understand the topic.
If you enjoyed the tutorial, give a LIKE to ENCOURAGE our WORK.
Subscribe to this channel, to watch more such videos.