Why do elements need to be heated to emit color?

A water pump draws about 9 A when connected to 240 V. What is the cost (with electrical energy at 13 cents per kWh) of running the pump for 16 h? (Give your answer in dollars)

A car traveling comes to a stop at a red light. How many forces are taking place?

What is the process called in which water vapor and carbon dioxide retain heat

In the fall of 2002, a group of scientists at los alamos national laboratory determined that the critical mass of neptunium-237 is about 60.0kg.

An echo is an example of A. Refraction B. Diffraction C. Reflection D. Destruction

A train moves at constant velocity of 50km/h. how far will it move in 0.5h?

Which process best describes part of a scientific investigation? O designing a solution O evaluating the conclusion O evaluating the solution O identifying the conclusion

How many neutrons are in Cesium-130

You are standing outside during the daytime. How can you see a blade of grass? A. Light is produced by your eyes and travels out to the grass. B. Light is produced by the grass and travels straight to your eyes. C.

Are cosmic rays and gamma rays invisible or do they have color?