Ceiling-mounted fluorescent lighting fixtures with total power equal to 400 W are used to produce an average illumination level of 600 lux on student desks in a particular classroom. If the classroom lights are on 10 hours a day for 200 days per year, calculate the annual energy used for lighting in this classroom.

A 800 kWh
B 2 kWh
C 2,000 Wh
D 2,000 kWh
E 800,000 kWh
F 600 kWh

How would you place two electrons on a sphere of radius r so that the electrostatic potential energy is minimized. how would you place three electrons to solve the same problem.

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

An object is 10 cm from the mirror, its height is 1 cm and the focal length is 5 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1 -1 +10 -10