# math

posted by .

The brightness of a light bulb varies inversely as the square of the distance from the source. If a light bulb has a brightness of 300 lumens at 2 ft, what will its brightness be at 10 ft?

## Similar Questions

1. ### math

The brightness of a light bulb varies inversely as the square of the distance from the source. If a light bulb has a brightness of 300 lumens at 2 ft, what will its brightness be at 10 ft?
2. ### physics

You are in the lab with a 10 V battery. You have a 10 W light bulb and you want to put 1/2 A of current through the light bulb and 5 V across the light bulb. This will allow the light bulb to have a brightness proportional to 2.5 W. …
3. ### college physics

You are in the lab with a 10 V battery. You have a 10 W light bulb and you want to put 0.75 A of current through the light bulb and 7.5 V across the light bulb. This will allow the light bulb to have a brightness proportional to 5.625 …
4. ### Physics

What happens to the brightness of light emitted by a light bulb when the current in the filament increases?
5. ### Physics

The brightness of a light source at a distance of 100m from the source is 40 units. What would be the brightness if the distance is reduced to 50m?
6. ### Math

A variable star is one whose brightness alternately increases and decreases. For one such star, the time between periods of maximum brightness is 5.6 days, the average brightness (or magnitude) of the star is 5.5, and its brightness …
7. ### algebra

The intensity I of light bulb measured in watts per square meter (w/m^2), varies inversely as the square of the distance d from the light bulb . . suppose I is 45 w/m^2 when the distance is 5 m . find the intensity when the distance …
8. ### math

The intensity of I of light from a light bulb, measured in watts per square meter (w/m^2), varies inversely as the square of the distance d from the light bulb. Suppose I is 85 w/m^2 when the distance is 5m. Find the intensity when …
9. ### Math

the intensity l of light from a light bulb, measured in watts per square meter (w/m^2), varies inversely as the square of the distance d from the light bulb. Suppose l is 70 w/m^2 when the distance is 5m. Find the intensity when the …
10. ### Calculus 1

A variable star is one whose brightness alternately increases and decreases. For one such star, the time between periods of maximum brightness is 4.7 days, the average brightness (or magnitude) of the star is 5.3, and its brightness …

More Similar Questions