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

29,203 results
  1. 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 source to receive twice as

  2. 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 is a constant. If the

  3. 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 from the light bulb is

  4. natali

    A 100W light bulb is left on for 10hrs. Over this period of time how much energy is used by the bulb? am i doing this right? my guess is to convert 100W to kW and convert 10 hrs to seconds and multiply the 2 together? which gives 3600J or should i just

  5. 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?

  6. Science

    1. Light bulbs produce useful energy in the form of light and waste energy in the form of heat. What kind of light bulb would you use to incubate eggs? A) high-efficiency light bulbs because they produce more heat B) High efficiency light bulbs because

  7. 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) that gives the distance of

  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 the distance from the

  9. Optics

    The famous Chinese magician Foo Ling Yu performs a classic magic trick using a concave mirror with a focal length of 1.6 m. Foo uses the mirror to produce an image of a light bulb that is the same size as the light bulb itself and is at the same location.

  10. Physics

    A 100 watts light bulb has an average life of 2000 hours. How much energy does it consume over its lifetime? The only thing I got was power=100 watts and time = 2000 hours but I need to convert to seconds and I don't kn how to do that.

  11. Physics

    We can reasonably model a 75 W incandescent light bulb as a sphere 6.0 cm in diameter. Typically, only about 5% of the energy goes to visible light; the rest goes largely to non-visible light infrared radiation. (a) What is the visible light intensity (in

  12. Energy question

    How would a $10.00 compact fluorescent light bulb (15 W) be an overall money saver compared to an incandescent light bulb (60 W) that costs $0.50?

  13. Math

    The intensity of light passing through a lens can be found using the formula I=Io - Io / csc^2 theta, where Io is the intensity of the light coming in, I is the intensity of the light that emerges or goes out of the lens, and theta is the angle between. a)

  14. 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 mix of polarisations, so

  15. IPC

    Explain whether the photons emitted by a bright light bulb are more energetic than those emitted by a dim light bulb of the same color. how does the color of the light bulb determine the amount of energy of the electromagnetic waves?

  16. 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

  17. circuits physics

    A 60 Watt light bulb draws 0.5 A of current. a. What is the voltage across the light bulb? b. What is the resistance of the light bulb?

  18. Physics

    We can reasonaly model a 75 W incandescent lightbulb as a sphere 6 cm in diameter. Typically, only about 5% of the energy goes to visible light; the rest goes largely to nonvisible infrared radiation. (a) What is the visible light intensity (in W/m^2) at

  19. brain teaser

    You are standing outside a closed door. On the other side of the door is a room that has three light bulbs in it. The room is completely sealed off from the outside. It has no windows and nothing can get in or out except through the door. On the outside of

  20. Analytic Geometry(Math)

    a person 6 ft. tall s standing near a street light so that he is 4/10 of the distance from the pole to the tip of his shadow. How high above the ground is the light bulb? if the person's head is exactly 5ft from the light bulb. how far is the person from

  21. Physics

    A 100 watts light bulb has an average life of 2000 hours. How much energy does it consume over its lifetime? The only thing I got was power=100 watts and time = 2000 hours but I need to convert to seconds and I don't kn how to do that.

  22. Physics

    A 100 watt bulb emits light in all directions. The distance R from the bulb is equal to 1.0 meter. Complete the table below with calculated values of intensity of the bulb. Distance from Source Intensity (W/m2) R ? 2R ? 3R ? c) If the bulb was replaced by

  23. physics

    Light is shining perpendicularly on the surface of the earth with an intensity of 680 W/m2. Assuming that all the photons in the light have the same wavelength (in vacuum) of 478 nm, determine the number of photons per second per square meter that reach

  24. PHYSICS

    Light is shining perpendicularly on the surface of the earth with an intensity of 680 W/m2. Assuming that all the photons in the light have the same wavelength (in vacuum) of 478 nm, determine the number of photons per second per square meter that reach

  25. 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 distance from the light

  26. Pre-Calc

    The intensity I of light received from a source varies inversely as the square of the distance d from the source. If the light intensity is 5 foot-candles at 17 feet, find the light intensity at 16 feet.

  27. 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?

  28. physics

    A student wants to compare the luminous flux of a light bulb with that of a 1675 lm lamp. The light bulb and the lamp illuminate a sheet of paper equally. The 1675 lm lamp is 1.28 m away from the sheet of paper; the light bulb is 1.08 m away. What is the

  29. statistics

    Suppose that the certain lifetimes of a certain light bulb are normally distributed with μ=1500 hours and σ=200. Find the probability that a light bulb will burn out in less than 1200 hours.

  30. mathematics

    A photographer uses a light meter to measure the intensity of light from a flashbulb. The intensity for the flashbulb, I, in lux, is a function of the distance from the light, d, in metres, and can be represented by I(d)=10/d^2,d>0 a) Determine the

  31. Physics

    A 100.0 W light bulb hangs from the ceiling. What is the visible light intensity on the floor, 2.1 m directly below the bulb, if 10% of its output is visible light? So I am attempting to use: I= Power/area however, I don't have a radius. I know 10% of 100

  32. math

    If the variance of a light bulb is 400 and the mean lifetime of a light bulb is 600 hours. find the probablity of a light bulb lasting at most 622 hours

  33. statistics

    Some college students collected data on the intensity of light at various depths in a lake. Here are their data: Depth (meters) Light intenisty (lumens) 5 168.00 6 120.42 7 86.31 8 61.87 9 44.34 10 31.78 11 22.78 Take the natural logarithm (ln) of the

  34. 8th grade Physics

    Explain whether the photons emitted by a bright light bulb are more energetic than those emitted by a dim light bulb of the same color. How does the color of the light bulbs determine the amount of energy of the electromagnetic waves?

  35. algebra 1

    Fiber-optic cables are used widely to increase the speed and accuracy of data transmission. When light passes through a fiber-optic cable, its intensity decreases with the increase in the length of the cable. If 1700 lumens of light enters the cable, the

  36. physics

    Light bulb packages will have at least two numbers on them; a power and what the potential difference across the bulb must be so that the bulb has the listed power. You go to the store and purchase two light bulbs. The package for Bulb A says 40 W in a

  37. math

    One light bulb is selected at random from a lot of 150 light bulbs, of which 6% are defective. What is the probability that the light bulb selected is defective?

  38. 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 W. Assuming any

  39. 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. Assuming any resistors

  40. Physics

    Two light bulbs are connected in series. The resistance of the filament of the first light bulb is 230Ω. The potential difference across the first light bulb is 100V and across the second light bulb,200V. What is the resistance of the second light bulb?

  41. Physics

    Multiple-Concept Example 9 reviews the concepts that are important to this problem. A light bulb is wired in series with a 116-Ω resistor, and they are connected across a 120.0-V source. The power delivered to the light bulb is 20.7 W. What is the

  42. Calc

    The rate (in mg carbon/m3/h) at which photosynthesis takes place for a species of phytoplankton is modeled by the function below, where I is the light intensity (measured in thousands of foot-candles). P = (120 I) / (I^2 + I + 1) For what light intensity

  43. Math

    You can buy an energy-saving light bulb for $18.07, which can work for 10,000 hours. It costs you 0.8 cents to operate it for an hour. ($1=100 cents). A regular light bulb with the same intensity costs 39 cents. The light bulb can work for 1000 hours. It

  44. 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 emitted by the bulb during its

  45. Science/Mathematics

    What is the intensity in W/m2 of a 80 -W light bulb at a distance 10 cm from the bulb's center?

  46. 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?

  47. physics

    Linearly polarized light is incident on a piece of polarizing material. What is the ratio of the transmitted light intensity to the incident light intensity when the angle between the transmission axis and the incident electric field is (a) 30° and (b)

  48. physics

    A 60W light bulb is connected to a 120V outlet. How long in seconds does it take for 1 billion (109) electrons to pass through the light bulb?

  49. physics

    A light bulb, after it has reached its operation temperature, is connected across a potential difference of 120V while 0.5A of current passses through it. What is the resistance of the light bulb?

  50. statistics

    Write the null and alternative hypotheses. Justify which is the claim. A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is less than 900 hours

  51. physics

    The current through a light bulb connected across the terminals of a 120 V outlet is 0.25 A. At what rate does the bulb convert electric energy to light 1Your answer was incorrect, but has changed from what was graded. W

  52. physics

    A 100W light bulb is left on for 10hrs. Over this period of time how much energy is used by the bulb? am i doing this right? my guess is to convert 100W to kW and convert 10 hrs to seconds and multiply the 2 together? which gives 3600J or should i just

  53. physics

    The sugar concentration in a solution (e.g., in a urine specimen) can be measured conveniently by using the optical activity of sugar and other asymmetric molecules. In general, an optically active molecule, like sugar, will rotate the plane of

  54. algebra

    Light intensity of water equation log I/12=-0.0125 What depth will the light intensity be half that of surface?

  55. 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 order to be illuminated as

  56. math

    The intensity I of light from a light​ bulb, measured in watts per square meter ​(w/m2​), varies inversely as the square of the distance d from the light bulb. Suppose I is 60 ​w/m2 when the distance is 3 m. Find the intensity when the distance

  57. Algebra

    The intensity of the light from the bulb is inversely proportional to its square of the distance from the bulb. If the intensity is 65 watts per square meter when the distance is 12 m, find the intensity at the distance of 24 m

  58. physics

    Unpolarized light from an incandescent lamp has an intensity 112.0 Cd as measured by a light meter. a) What is in Cd the intensity reading on the meter when a single ideal polarizer is inserted between the bulb and the meter? b) What is in Cd the intensity

  59. Physics/Algebra

    Physics: For a 225-watt bulb, the intensity I of light in lumens at a distance of x feet is I=225/x^2. a. What is the intensity of light 5 ft from the bulb? b. Suppose your distance from the bulb doubles. How does the intensity of the light change?

  60. algebra

    Because a stadium will be used at night, lights have been installed. The brightness (B) of a light varies directly with the intensity (I) of the light and inversely as the square of the distance (D) from the light. Brightness (B) is measured in light

  61. Introduction to Electricity and Circuits

    A light bulb is wired in series with a 142 resistor, and they are connected across a 120 V source. The power delivered to the light bulb is 22.3 W. What are the two possible resistances of the light bulb?

  62. physics

    A light bulb is wired in series with a 133-Ω resistor, and they are connected across a 120-V source. The power delivered to the light bulb is 22.5 W. What are the two possible resistances of the light bulb?

  63. Calculus

    The rate (in mg carbon/m3/h) at which photosynthesis takes place for a species of phytoplankton is modeled by the function P = 110I I2 + I + 4 where I is the light intensity (measured in thousands of foot-candles). For what light intensity is P a maximum?

  64. Calculus

    The rate (in mg carbon/m3/h) at which photosynthesis takes place for a species of phytoplankton is modeled by the function P = 110I I2 + I + 4 where I is the light intensity (measured in thousands of foot-candles). For what light intensity is P a maximum?

  65. math

    The rate (in mg carbon/m3/h) at which photosynthesis takes place for a species of phytoplankton is modeled by the function P = 100I / I2 + I + 9 where I is the light intensity (measured in thousands of foot-candles). For what light intensity is P a

  66. Calculus 1

    The rate (in mg carbon/m^3/h) at which photosynthesis takes place for a species of phytoplankton is modeled by the function P = (120I)/(I^2 + I + 4) where I is the light intensity (measured in thousands of foot-candles). For what light intensity is P a

  67. College Physics

    The power dissipated by a light bulb increases by 50 W when the potential difference applied across the light bulb increases from 50 V to 100 V. Find the resistance of the light bulb.

  68. physics

    The angle between the polarizer transmission axis and the plane of polarization of the incoming light is 30 +/- 2 deg. If the incident light intensity Io is 100 W/cm2 what would be the intensity I after the light is transmitted through the polarizer? What

  69. analogies

    furnace:fireplace::lamp: ? log,street light,light bulb, headlight,candle is light bulb correct?

  70. physics

    Light is shining perpendicularly on the surface of the earth with an intensity of 680 W/m2. Assuming that all the photons in the light have the same wavelength (in vacuum) of 521 nm, determine the number of photons per second per square meter that reach

  71. physical

    Light is shone on a metal and photoelectrons are emitted. Can you tell me the three things from the list below which might cause the photoelectron emission to stop. Decreasing the intensity of the light Increasing the frequency of the light Decreasing the

  72. electrical circuit

    When a second light bulb is wired into an electric circuit already containing one light bulb, the first one dims. What kind of circuit is the light bulb wired into? open circuit! Yes! No. The bulb is wired into a SERIES circuit. If the first bulb did not

  73. physic

    Light is shone on a metal and photoelectrons are emitted. Can you tell me the three things from the list below which might cause the photoelectron emission to stop. Decreasing the intensity of the light Increasing the frequency of the light Decreasing the

  74. science

    Light is shone on a metal and photoelectrons are emitted. Can you tell me the three things from the listbelow which might cause the photoelectron emission to stop. Decreasing the intensity of the light Increasing the frequency of the light Decreasing the

  75. physics

    Light is shone on a metal and photoelectrons are emitted. Can you tell me the three things from the listbelow which might cause the photoelectron emission to stop. Decreasing the intensity of the light Increasing the frequency of the light Decreasing the

  76. grammar check

    which is a compound subject? 1) my sister and i saw a dinosaur at the museum. 2) marco polo lived in italy and explored places in china.i choose number 1. identif the complete predicate. thomas edison invented the light bulb, among other things. d)invented

  77. maths

    the life span of an electric bulb is normally distribution with mean 5500 light hours and standard deviation of 1200 light hours . what is the probability that a randomly selected bulb which lasts more than 6000 light hours?

  78. math

    after passing therough a material t centimeters thick, the intensity I(t) of a light beam is given by I(t) =(4^-ct)Io, where Io is the initial intensity and c is a constant called the absorption factor. Ocean water absorbs light with an absorption factor

  79. algebra worksheet help please

    Fiber-optic cables are used widely for Internet wiring, data transmission, and surgeries. When light passes through a fiber-optic cable, its intensity decreases with the increase in the length of the cable. If 1,500 lumens of light enter the cable, the

  80. Physics - solar power in space

    Hi, this requires some basic knowledge of astrophysics. I missed last lecture that covered this, so though I'd prefer thorough solutions to these problems, I'd appreciate it even if you could tell me which formulas to use to solve each part of the problem.

  81. algebra

    Fiber-optic cables are used widely for internet wiring, data transmission, and surgeries. When light passes through a fiber-optic cable, its intensity decreases with the increase in the length of the cable. If 1500 lumens of light enters the cable, the

  82. Physics

    How would you make a light bulb light up with one battery, one light bulb, and ONE wire?

  83. Physics

    If a light bulb draws 60 watts and I leave it on for 5 hours, how much energy has been consumed?

  84. Physics Energy

    How would a $10.00 compact fluorescent light bulb (15 W) be an overall money saver compared to an incandescent light bulb (60 W) that costs $0.50?

  85. Physics

    Could you please check these? The work of which scientist(s) helped to explain light's ability to propagate through a vacuum? ++A. Maxwell B. Davisson and Germer C. Fresnel, Fraunhofer, and Arago D. Newton An object that has a height of 0.4 meter is placed

  86. college

    a light bulb manufacture claims that the mean life of a certain type of light bulb is more than 750 hours

  87. math

    1) A light bulb producing company states that its lights will last an average of 1200 hours with a standard deviation of 200 hours. A sample of 100 light bulbs from the company were tested and the researcher found that the average life of each light bulb

  88. Physical Science

    1.Nico uses wire to connect a battery, light bulb, and a switch, but the light bulb doesn't light up. What might explain this problem? A.The circuit is closed B.The wires are bent C.The battery has too much power D.The switch is open. B? 2.What type of

  89. physical science

    there is current of 0.65a through a light bulb in a 120v circuit what is the resistance of this light bulb?

  90. geometry

    A person 6 ft tall is standing near a treet light so that he is 4/10 of the distance from the pole to the tip of his shadow.How high above the ground is the light bulb? If the persons head is exactly 5ft from the light bulb how far is the person from the

  91. Physics

    A 100-watt bulb becomes warm and glows brightly enough to light a small room. On the other hand, a 100-watt laser can cut holes in steel and would not be effective at lighting a small room. What is true about the light coming from these two sources that

  92. physics Damon???

    The sugar concentration in a solution (e.g., in a urine specimen) can be measured conveniently by using the optical activity of sugar and other asymmetric molecules. In general, an optically active molecule, like sugar, will rotate the plane of

  93. much needed help...

    The sugar concentration in a solution (e.g., in a urine specimen) can be measured conveniently by using the optical activity of sugar and other asymmetric molecules. In general, an optically active molecule, like sugar, will rotate the plane of

  94. physics

    The sugar concentration in a solution (e.g., in a urine specimen) can be measured conveniently by using the optical activity of sugar and other asymmetric molecules. In general, an optically active molecule, like sugar, will rotate the plane of

  95. Calculus can you please show me the step by step s

    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 order to be illuminated as

  96. physics

    Hello I'm having trouble with this physics question: You are examining the loss in intensity as light passes through a fibre optic cable. The input intensity is measured as 55.1 W/m2 and the output intensity as 28.7 W/m2. Calculate the attenuation of the

  97. physics ( help FAST)

    if you were to move the light sencor in an experiment 5 times further from the light as it was before, by what fraction would the light intensity change????

  98. Physic

    CFL light bulbs consume less power than their incandescent counterparts while providing about the same amount of light. Suppose a CFL, while consuming only 20 Watts of power produces as much light as a 60 Watt incandescent bulb. Also, suppose a house has 8

  99. college

    the inverted image of a light bulb is formed on a screen located 9 metres from spherical mirror.the image is 4 times larger than the light bulb.determine the object distance

  100. Precalc

    Can someone please help me? I don't know how to solve for time under 23 units. When I try I think I get the answer for above 23 units and when I try to subtract from the whole period my answer is wrong. The correct answer is 5.1337 hours. Fidel is

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