Krypton-85 has a half-life of 10.76 years. It decays into rubidium-85. Suppose a sample contains 4 atoms of krypton-85 and 12 atoms of rubidium-85.
About how old is the sample?
A. 10.76 years
B. 21.52 years
C. 43.04 years
D. 32.28 years

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.​

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.

cancer risk hope this

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray