College Algebra

Intensity of Light. The intensity I of light from a light bulb varies inversely as the square of the distance d from the bulb. Suppose that I is
90
W
/
m
2
90W/m2 (watts per square meter) when the distance is 5 m. How much farther would it be to a point where the intensity is
40
W
/
m
2
40W/m2?

  1. 👍
  2. 👎
  3. 👁
  1. I = k/d^2
    so, Id^2 = k is constant

    So, find d such that

    40d^2 = 90*5^2

    and subtract 5

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. 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

  2. Math

    The intensity of Illumination on a surface varies inversely as the square of the distance from the light source. A surface is 12 meters from a light source and has an intensity of 2. How far must the surface be from the light

  3. algebra

    The light intensity of a light bulb varies inversely as the square of the distance from the light bulb. The function I(d) = k/d^2 models this situation, where I is the light intensity, d is the distance from a light source, and k

  4. Physics

    Unpolarised light of intensity 4.0Wm^−2 is incident on a polariser placed at 15∘ to the vertical. State the intensity of the transmitted light. I've tried 4 x cos(15)^2 = 3.732050808, but it says "Unpolarised light is a random

  1. Calculus

    The intensity of light varies inversely as the square of the distance from its source. If two searchlights are 600 meters apart and one light is 8 times as strong as the other, where should a man cross the line between them in

  2. Algebra 2

    The intensity of the light from an object varies inversely with the square of the distance. In other words, I = k over d^2 a. Solve the equation to find d in terms of I. b. Two stars give off the same amount of light. However,

  3. Pre Cal

    The intensity of light decreases by 4% for each meter that it descends below the surface of the water. At what depth is the intensity of light only 20% of that at the surface?

  4. physics

    Unpolarized light is incident on four polarizing sheets with their transmission axes oriented as shown in the figure, in which θ1 = 27.0° and θ2 = 50.0°. What percentage of the initial light intensity is transmitted through

  1. Math

    A fly starts out 2 meters from a light bulb, flies closer to the light then farther away, 2 meters again. At this point the fly goes toward the bulb again but hits the bulb and flies away. Find a function (it may be piecewise)

  2. Physics

    A special kind of light bulb emits monochromatic light of wavelength 630 nm. Electrical energy supplied to it at the rate of 60W, and the bulb is 93% efficient at converting that energy into light energy. How many photons are

  3. Physics

    I need help on this question: You are given information on the intensity level (which is a measure of the sound intensity) at a point and its distance from the sound source. To make use of this information, you will need to

  4. Math - Logorithms

    The intensity, I, of light, in lumens, passing through the glass of a pair of sunglasses if given by the equation I(x) = I^o(0.8)^x, where x is the thickness of the glass, in millimeters, and I^o is the intensity of light entering

You can view more similar questions or ask a new question.