# Problem: A 60-W light bulb radiates electromagnetic waves uniformly in all directions. At a distance of 1.0 m from the bulb, the light intensity is I0, the average energy density of the waves is u0, and the rms electric and magnetic field values are E0 and B0, respectively.1. At 2.0 m from the bulb, what is the light intensity?2. At 2.0 m from the bulb, what is the rms magnetic field value?3. At 2.0 m from the bulb, what is the average energy density of the waves?

###### FREE Expert Solution

1. Light intensity:

$\overline{)\begin{array}{rcl}\frac{\mathbf{I}}{{\mathbf{I}}_{\mathbf{0}}}& {\mathbf{=}}& \frac{{{\mathbf{r}}_{\mathbf{0}}}^{\mathbf{2}}}{{\mathbf{r}}^{\mathbf{2}}}\\ {\mathbf{I}}& \mathbf{=}{\mathbf{I}}_{\mathbf{0}}& \mathbf{\left(}\frac{{{\mathbf{r}}_{\mathbf{0}}}^{\mathbf{2}}}{{\mathbf{r}}^{\mathbf{2}}}\mathbf{\right)}\end{array}}$

92% (42 ratings) ###### Problem Details

A 60-W light bulb radiates electromagnetic waves uniformly in all directions. At a distance of 1.0 m from the bulb, the light intensity is I0, the average energy density of the waves is u0, and the rms electric and magnetic field values are E0 and B0, respectively.

1. At 2.0 m from the bulb, what is the light intensity?

2. At 2.0 m from the bulb, what is the rms magnetic field value?

3. At 2.0 m from the bulb, what is the average energy density of the waves?

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Energy Carried by Electromagnetic Waves concept. You can view video lessons to learn Energy Carried by Electromagnetic Waves. Or if you need more Energy Carried by Electromagnetic Waves practice, you can also practice Energy Carried by Electromagnetic Waves practice problems.

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Based on our data, we think this problem is relevant for Professor Barkan's class at UIC.