Question

Type 11 : Plane angle & Solid Angle
10. Calculate the solid angle subtended by the periphery of an area of 1 cm" at a point situated
symmetrically at a distance of 5 cm from the area.​

Answer 1

Answer:

Given data,

Area=1cm2

Distance=5cm

Solid angle Ω=?

We know the formula 

Solid angle Ω=(Radial distance)2Area

=(5cm2)1cm2=251

=4×10−2steradian

The solid angle is for 3−D figure like spere, cone, etc and plane angle is for plane objects or 2−D figure like circle,arc etc.