Question

The intensity of light from a light source vaties inversely as the square of the distance from the source. If the intensity of a light bulb is 48 lumen/m 2 (lux) at a
distance of 5 m, determine the intensity at 4 m.

Help plz

Answer 1

Answer:

• 75 lux

Step-by-step explanation:

Let the intensity is y and the distance is x.

Their relationship is:

• y = k / x², where k is the coefficient of proportionality

Let's substitute given values and find the value of k:

• 48 = k/5²
• k = 48*25
• k = 1200

Our equation becomes:

• y = 1200/x²

Now find the value of y when x = 4:

• y = 1200/4²
• y = 1200/16
• y = 75