Question
Wed July 18, 2012 By: Manisha

could you please explain me plane angle and solid angle clearly in simple lanigua

Expert Reply
Tue July 24, 2012
The plane angle is the angle we usually deal with.
Take a plane surface and take a point on it.
Now if we are standing on that point and we have a circle of radius r drawn centered on us. Thus if we view an arc (l), and the angle it sustends on the center is called the plane angle of that arc. It is calculated as according to the defination of radiuns as:
? = l/r
 
Now suppose in a 3-D space we are at a fixed point and we have  a sphere of unit radius centered on us, then for a surface(S) on that sphere the solid angle about that point P is defined as:

These are called surface integral and are exlained at a much later stage.
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