Thank you for helping me! You and your friend Bruce are experimenting with a red

Question

Thank you for helping me!

You and your friend Bruce are experimenting with a red lamp shade and blue lamp shade. You place lamp shades individually over a 120-W light bulb. Assume that the light radiates from the lamps uniformly and 6.2% of their power is converted to light.

(a) What is the average intensity of the light at 1.9 m from the red

(? = 710 nm)

lamp shade?
W/m2

(b) Is the average intensity of the blue

(? = 480 nm)

lamp shade at 1.7 m greater than, less than, or equal to the intensity calculated in part (a)?

greater thanless than    equal to

Explanation / Answer

The useful power is

P = 120 W * 0.062 = 7.44 W

As

I = P / (4 pi r^2)

Then

I = 0.164 W/m^2 [ANSWER]

*****************

It should be the same.

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