Which best blocks X-ray particles and can therefore be observed more closely through the use of this technology?

What is important to study for nios grade 12 chemistry? i have only one month left.

A100-watt light bulb radiates energy at a rate of 100 j/s. (the watt, a unit of power or energy over time, is defined as 1 j/s.) if all of the light emitted has a wavelength of 525 nm , how many photons are emitted per second?

What is the main reason why some developing countries fear the increase the free trade policies around the world?