Question

The kitchen in your house measures 10 ft by 10 ft. You need to have 50 footcandles of illumination in the room. How many 60 watt bulbs will be required if one bulb emits 834 lumens. (1 footcandle = 1 lumen/sq.ft)

Answer 1

Answer:

6 bulbs are needed to illuminate the room.

Explanation:

Given:

Measurement of kitchen (A) = 10 ft by 10 ft = 100 sq. ft

Number of footcandles (n) = 50

Lumens emitted by 1 bulb = 834

Number of bulbs (N) = ?

We are also given,

1 foot candle = 1 lumen/sq. ft

So, 50 foot candles = 50 lumens/sq. ft

Now, for an area of 1 sq. ft 50 lumens are emitted.

So, for an area of 100 sq. ft, lumens emitted = 50 × 100 = 5000 lumens

Now, one bulb emits = 834 lumes

Therefore, number of bulbs required for emitting 5000 lumens is given as:

$N=\frac{Number\ of\ lumens}{Number\ of\ lumens\ by\ 1\ bulb}\\\\N=\frac{5000}{834}=5.995\approx6$

So, 6 bulbs are needed to illuminate the room.