The table below compares the radioactive decay rates of two materials. Material Original mass of material (in grams) Mass of material after 21.6 seconds (in grams) 1 100 12.5 2 200 25 Based on the table, which of these conclusions is most likely correct? The half-life of Material 1 and Material 2 are equal. The half-life of Material 2 is double the half-life of Material 1. The half-life of Material 2 is 10.8 seconds more than the half-life of Material 1. The half-life of Material 1 is 10.8 seconds more than the half-life of Material 2.

Material Original mass of material (in grams) Mass of material after 21.6 seconds (in grams)
1 100 12.5
2 200 25

The half-life of Material 1 and Material 2 are equal.

Explanation:

Material 1 disintegrates to half its mass three times in 21.6 s, to go from 100g

to 12.5g. That is,

100g - 50g - 25g - 12.5g

Material 2 disintegrates to half its mass three times in 21.6 s, to go from 200g to 25g. That is,

200g - 50g - 25g - 12.5g.

This means that regardless of their initial masses involved, material 1 and material 2 have equal half-life.

Their half-life is 21.6 ÷ 3 = 7.2 sec

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.