a. If the luminous intensity at 0° angular displacement is 3.0 mcd for the device of Fig....

a. If the luminous intensity at 0° angular displacement is 3.0 mcd for the device of Fig. 1.52 at what angle will it be 0.75 mcd?

b. At what angle does the loss of luminous intensity drop below the 50% level?

FIG. 1.52 Hewlett-Packard subminiature high-efficiency red solid-state lamp: relative luminous intensity versus angular displacement.