Lumens

Lumen (Im) is the unit of luminous flux, which is the measure of the total power emitted by the source.  This is a standard way of measuring the brightness of a light.  To give you an idea, a 100 watt  light bulb is approximately 1700 lumens and a 40 watt bulb is about 500 lumens.

Colour Temperature (Kelvin)

Colour temperature is a characteristic of visible light that has important applications in lighting. The colour temperature of a light source is the temperature of an ideal black-body radiator that radiates light of comparable hue to that light source.  The temperature is conventionally stated in units of absolute temperature, kelvin (K).   Higher colour temperatures (5,000 K or more) are called cool colors (blueish white); lower colour temperatures (2,700–3,000 K) are called warm colors (yellowish white through red).