omi 16

Question 1

what is a solid angle (steradians (sr))

Answer 1

a measure of amount of field of view from some particular point that a given object covers; it is how large the object appears to an observer looking from that point. it represents a cone.

Question 2

luminous flux (lumen (lm))

Answer 2

measure of power of perceived power of light
the light is emitted by a source or received by a surface

it is the energy per unit time radiated from a source over visible wavelengths , it is. weighted average as human eye does not respond equally to all visible wavelengths

Question 3

luminous intensity (candela (cd))

Answer 3

the quantity which describes the power of a source or illuminated surface to emit light in a given direction

Question 4

illuminance (lux (lx))

Answer 4

the luminance flux density at a point on a surface i.e. the luminous flux incident per unit area

Question 5

luminance (cd m-2)

Answer 5

the intensity of the light emitted in a given direction per projected area of luminous or reflecting surface