A color television tube generates some X-rays when its electron beam strikes the screen. What is the shortest wavelength of these X-rays, in meters, if a 31 kV potential is used to accelerate the electrons? (Note that TVs have shielding to prevent these X-rays from reaching viewers.)

 4.0024 x 10^ -11 m or 0.040024 nm

Explanation:

λ = h c/ΔE

λ = wave lenght

h = 6.626 x 10 ^ -34  m² kg /s  = planck constant

ΔE = 31 keV potential ( 1 keV = 1.6021 x 10^-16J)

c = velocity of light = 3 x 10⁸ m/s

substitute gives

λ  =    6.626 x 10 ^ -34  m² kg /s x 3 x 10⁸ m/s  = 4.0024 x 10^ -11 m

                 31 x 1.6021x10^-16 J

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​

the journeys of marquette, joliet and la salle a) new france expand.

all three of these explorers explored the midwest and the area around the great lakes, which they subsequently claimed for france.

this was a big portion of territory and expanded new france which before then only consisted of quebec province in northeastern canada