Potassium has a half-life of 12 hours. What fraction of a 100g sample is left after 48 hours

After 48 hours amount left = 6.25 g

Explanation:

Given data:

Half life of potassium = 12 hours

Total mass = 100 g

Mass left after 48 hours = ?

Solution:

Number of half lives passed:

Number of half lives = Time elapsed / half life

Number of half lives = 48 hours/ 12 hours

Number of half lives = 4

At time zero = 100 g

At first half life = 100 g/ 2 = 50 g

At 2nd half life = 50 g/2 = 25 g

At 3rd half life = 25 g/2 = 12.5g

At 4th half life = 12.5 g/2 = 6.25 g

ans.

dna fingerprinting is defined as a process that determines the dna characteristics of an individual. these dna characteristics are unique among individuals as their fingerprints, so it is known as dna fingerprinting.

steps of dna fingerprinting includes extraction of dna from sample, amplification of dna, restriction digestion of amplified dna, and then analysis of dna by gel electrophoresis, respectively.

thus, the next step performed by the scientist is 'to cut the amplified dna (obtained by polymerase chain reaction) by restriction enzymes that cleave the dna into fragments and their analysis.'