The unit for measuring the rate at which light energy is radiated from a source is called the candela. Its symbol is cd. It is the SI unit for luminous intensity or luminous power per unit solid angle emitted by a point light source in a particular direction. On the other hand, lumen is unit used to measure the amount of light intensity emitted by a surface.
the unit for measuring the rate at which light energy is radiated from a source is the ?