# How Much Force Does Sunlight Exert on Earth?

• machinarium
In summary, the intensity of radiation from the sun reaching the Earth is 1350 W/m2. Assuming all of it is absorbed, the force exerted on the Earth is approximately 2.3 x 109 N. This is different from the result of 5.8 x 108 N provided in the material. Additionally, there is confusion about the difference between I or Sav and S in calculations, as well as the correct equation to use for calculating total power. Some sources use P=SavA while others use Pav=SavA, and it is unclear if Pav is the same as P. In regards to calculating power, the precise equation is instantaneous power = instantaneous intensity times area, but since it is difficult to measure instantaneous
machinarium

## Homework Statement

The intensity of radiation reaching the Earth from the sun is 1350 W/m2. The Earth's radius is 6.4 × 106 m. How big a force does this radiation exert on the Earth (Assume it is all absorbed)

## The Attempt at a Solution

F=AP=AI/c=2.3x109 N

That's my answer. Is that correct?

(The result in my material is 5.8x108 N)

And I want to ask one more question?
What is the difference between I or Sav and S in calculation?
If we say the Sun delivers about 10000 W/m2 of energy to the Earth's surface, so that is Sav, right?

Then they told me to calculate the total power.

I see a book solved by telling P=SavA and another book was Pav=SavA.

Which one was correct? Or was Pav the same as P?
Then is this one P=SA.

hi machinarium!

did you square the diameter?

the precise equation is instantaneous power = instantaneous intensity times area …

and therefore average power = average intensity times area …

in AC electric circuits the difference between instantaneous power and average instantaneous is quite important, and with lasers also, but I don't see how you could measure instantaneous power or intensity for an incoherent source like sunlight, so that has to be average (so there's not much point in saying so)

## What is the force exerted by radiation?

The force exerted by radiation is the pressure or push that radiation exerts on an object. This force is caused by the transfer of energy from the radiation to the object.

## How is the force exerted by radiation measured?

The force exerted by radiation can be measured using a device called a radiometer. This device uses the radiation pressure to spin a small rotor, which can then be measured and converted into force units.

## What factors affect the force exerted by radiation?

The force exerted by radiation can be affected by several factors, including the intensity and wavelength of the radiation, the distance between the radiation source and the object, and the size and shape of the object itself.

## Can the force exerted by radiation be harmful to humans?

In most cases, the force exerted by radiation is not harmful to humans. However, high levels of radiation exposure can cause damage to cells and tissues, leading to health issues such as radiation sickness and increased risk of cancer.

## How is the force exerted by radiation used in technology?

The force exerted by radiation is used in a variety of technologies, such as solar sails, laser propulsion systems, and radiation pressure sensors. It is also used in medical imaging techniques, such as X-rays and radiation therapy.

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