Recommended illumination range satisfactory vision is ---- foot candles: (A) 15-20, (B) 25-50, (C) 51-75, (D) 76-100
Answer is A. An illumination of 15-20 footcandles (1 foot-candle = 10.76 Lux) is accepted as a basic minimum for satisfactory vision.Park 23e pg: 739