An x-ray tube contains a target consisting of atoms with z = 44. the high voltage in this tube is increased from zero. using the bohr model, find the value of the voltage at which the x-ray just appears in the x-ray spectrum.

Ineed asap! list 3 examples in which friction us or makes things easier in our daily life. explain the effect of friction for each. *make sure you explain the effect of friction for each example! *

Because atoms of elements in the same group of thbecause atoms of elements in the same group of the periodic table have the same number of neutrons, they have similar properties. select the best answer from the choices provided t fe periodic table have the same number of neutrons, they have similar properties. select the best answer from the choices provided t f

Awelder using a tank of volume 7.50×10^-2 m^3 fills it with oxygen (with a molar mass of 32.0 g/mol ) at a gauge pressure of 3.30×10^5 pa and temperature of 37.1 ∘c. the tank has a small leak, and in time some of the oxygen leaks out. on a day when the temperature is 23.1 ∘c, the gauge pressure of the oxygen in the tank is 2.00×10^5 pa . a) find the initial mass of oxygen. b) find the mass of oxygen that has leaked out.