A single-story retail store wishes to supply all its lighting requirement with batteries charged by photovoltaic cells. The PV cells will be mounted on the horizontal rooftop. The time-averaged lighting requirement is 10 W/m2 , the annual average solar irradiance is 150 W/m2 , the PV efficiency is 10%, and the battery charging/discharging efficiency is 80%. What percentage of the roof area will the PV cells occupy

83.33% of the roof area will be occupied by the PV cells

Explanation:

Given the data in the question;

time-averaged lighting requirement = 10 W/m²

the annual average solar irradiance = 150 W/m²

the PV efficiency η = 10% = 0.1

battery charging/discharging efficiency η = 80% = 0.8

we know that; Annual average power to the light = × A

Now, the electrical power delivered by the solar cell battery system will be;

⇒   × A × η × η

A = × A × η × η

Such that;

A = A / × A × η × η

A / A = /   × η × η

so we substitute

A / A = 10 W/m² / [ 150 W/m² × 0.1 × 0.8 ]

A / A = 10 W/m² / 12 W/m²

A / A = 0.8333

A / A = (0.8333 × 100)%

A / A = 83.33%

Therefore, 83.33% of the roof area will be occupied by the PV cells.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

here are some information of the future of geothermal energy:

-the future of geothermal energy can pretty much be summed up with a single word: more

-scientists plan in going deeper than 120 meters

-we are hoping that one day, we will get all of our energy from renewable energy sources such as geothermal energy

hope this !