Health Hygiene & Sanitation

Lesson 16 : Lighting And Noise

Measurement Of Light

• Light is a band in the electromagnetic spectrum with wavelength of 380 – 780 nm
• Light with all visible waves is perceived as white
• Four measures of light are
• Luminous intensity-measured as ‘candela or candle power’
• Luminous flux-measured as ‘Lumen’
• Illumination or Illuminance-measured in ‘Lux’ per unit area, it is also ‘foot candle’
• Brightness or Luminance-measured as ‘lambert’

Recommended by the ‘International Organisation for Standardization’