# Sunlight, Intensity, electric field RMS

• ooohffff
In summary, the task was to estimate the rms electric field in the sunlight that hits Uranus, given the Earth's received power of 1350 W/m2 and Uranus being 19.2 times farther from the Sun. The solution involved using the equation for electric field and calculating the intensity for a distance 19.2 times greater, resulting in an answer of 37.14 V/m. The concept of assuming a constant electric field was also mentioned and verified by an alternative calculation.
ooohffff

## Homework Statement

Estimate the rms electric field in the sunlight that hits Uranus, knowing that the Earth receives about 1350 W/m2 and that Uranus is 19.2 times farther away from the Sun (on average) than is the Earth.

I=cεoErms2
E=V/d

## The Attempt at a Solution

Eearth=V/d
Since Uranus is 19.2 times farther away then:
Euranus=Eearth/19.2

Iearth = 1350 W/m2
Iearth=cεoEearth rms2
Euranus rms = Eearth rms / 19.2 = √ ( I / (cεo)) / 19.2
= 37.14 V/m

I got this problem wrong several times so I just wanted to verify that I did it right this time. Thanks!

Be aware that saying the electric field is equal to the electric potential divided by distance implies that you are assuming a constant electric field. In actuality the electric field equals the negative gradient of the potential.

TSny
But yes, that answer does look right. I just calculated it using the relation between power and intensity, calculating the intensity for a distance 19.2 times greater, and plugging into your equation, and I came out with 37.15 V/m.

Thanks! I got it right :)

## What is sunlight?

Sunlight is a form of electromagnetic radiation emitted by the sun, consisting of visible light, infrared radiation, and ultraviolet radiation.

## What is intensity?

Intensity is a measure of the amount of energy per unit time and per unit area that is transported by an electromagnetic wave, such as sunlight. It is typically measured in watts per square meter (W/m²).

## How is intensity of sunlight measured?

The intensity of sunlight can be measured using a device called a radiometer, which contains a set of vanes that rotate when exposed to the sun's radiation. The speed of rotation is proportional to the intensity of the sunlight.

## What is electric field RMS?

Electric field RMS (Root Mean Square) is a measure of the average strength of an electric field over a given period of time. It is calculated by taking the square root of the average of the squared values of the electric field over time.

## How does intensity affect electric field RMS?

The intensity of sunlight can affect the electric field RMS by increasing the strength of the electric field. This is because the intensity of sunlight is directly proportional to the energy of the electromagnetic wave, which in turn affects the strength of the electric field. Therefore, higher intensity sunlight will result in a higher electric field RMS.

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