किस प्रकार की प्रकाश व्यवस्था (illumination scheme) की दक्षता सबसे अधिक होती है?

is defined as the ratio of power input (in Watts) to the mean spherical candle power (MSCP) of a lamp.

In illumination engineering, the space-height ratio is defined as the ratio of:

Arrange the following lamps in the increasing order of their power rating and energy consumption required to provide the same level of illumination (based on their given efficacies): A. Incandescent Lamp with efficacy of 10 lumens/watt B. Compact fluorescent lamp (CFL) with efficacy of 60 lumens/watt C. Halogen lamp with efficacy of 20 lumens/watt D. Mercury vapour lamp with efficacy of 40 lumens/watt E. Light Emitting Diode (LED) lamp with efficacy of 80 lumens/watt Choose the correct answer from the options given below: