Landing Light bulbs

Why does the diameter of the reflector have so much effect on the
output-(candlepower)--of bulbs having the same power input?? i.e.
#4509-PAR-36 4.45"Ø 110,000cp
#4537-PAR-46 5.70"Ø 200,000cp

And then we have the newer import cars using 2.5" reflectors (+ a
condensing lens of similar dia.) which are apparently equal to the
larger rectangular bulbs of conventional design.

then there are the hand lanterns with QH peanut bulbs of 50 to 100 watts
boasting 500,000 to 1,000,000 cp. Jerry

Jerry Wass wrote:
Why does the diameter of the reflector have so much effect on the
output-(candlepower)--of bulbs having the same power input?? i.e.
#4509-PAR-36 4.45"Ø 110,000cp
#4537-PAR-46 5.70"Ø 200,000cp


The reflecting area is larger. 15.55 in^2 compared to 25.51 in^2

Gig 601XL Builder wrote:
Jerry Wass wrote:
Why does the diameter of the reflector have so much effect on the
output-(candlepower)--of bulbs having the same power input?? i.e.
#4509-PAR-36 4.45"Ø 110,000cp
#4537-PAR-46 5.70"Ø 200,000cp


The reflecting area is larger. 15.55 in^2 compared to 25.51 in^2


#4559-PAR-64 8.1"Ø= 600,000cp-(with 600 watts input)
would this equate to 100,000cp- (with 100 watts input)?--
Yet it's area is 51.5 1n²--or nearly 3.31 times as big as the 4509.