Tuesday

October 21, 2014

October 21, 2014

Posted by **saru** on Friday, October 18, 2013 at 1:25am.

Calculate the average solar power per square meter (in Watts) on a horizontal surface for a day when the sun goes through the zenith at noon.

The sun goes through the zenith exactly twice a year on latitudes that are close to the equator. Take the angle to the sun into account.

- Physics pls anyone can help me? its urgent -
**bobpursley**, Friday, October 18, 2013 at 3:56amThe incident power is given by

power=Powermax*sinTheta

where theta is the angle measured from horizontal East to the sun. At noon, Theta=90 degrees This takes 12 hours, so theta=time*PI/12, where time is in hours, ie, noon is time 6

avg=total energy /time

lets measure energy in kw-hr

total energy= INTEGRal power*dtime from time=0 to 12

total energy= INT 1kw*sin(PI*t/12 )dt

= -1kw* (cosPIt/12)*12/PI from zero to 12

= -12/PI * (cos (PI) -cos0)

= -12/PI ( -1 -1)=24/PI kw-hr

average power= total energy/(12)

= 2/PI kw-hrs

check this.

- Physics pls anyone can help me? its urgent -
**saru**, Friday, October 18, 2013 at 4:15amIt should be in watts. so 2/PI kw-hr should be 2*1000/(PI*3600)watts or ? please

- Physics pls anyone can help me? its urgent -
**Steve**, Friday, October 18, 2013 at 4:28amsomething got mangled in the units

kw-hr is energy

kw is power

Better check the units in the math above.

**Answer this Question**

**Related Questions**

Physics pls anyone can help me? its urgent - When the sun is in the zenith and ...

physics help - At a certain location, the solar power per unit area reaching the...

physics - At a certain location, the solar power per unit area reaching the ...

physics - The sun is 1.5 1011 m from the earth. (a) Over what surface area is ...

astrophysics - 1) Every second the Sun outputs 3.90* 10^26 Joules of energy. ...

astrophysics - 1) Every second the Sun outputs 3.90* 10^26 Joules of energy. ...

Astronomy - Where do you have to be on the Earth to see the Sun at your zenith? ...

physics - he sun radiates like a perfect blackbody with an emissivity of exactly...

physics - The sun radiates like a perfect blackbody with an emissivity of ...

Physics - The sun radiates like a perfect blackbody with an emissivity of ...