The half-life for a 100-gram sample of radioactive element X is 5 days. How much of element X remains after 10 days have passed?

A.
75 g

B.
50 g

C.
100 g

D.
25 g

25g

Explanation:

Given parameters:

    Half life of X = 5days

Mass of sample of radioactive elements  = 100g

The half-life of a radioactive material is the time it takes for a sample to decay by half. At the half-life, an original sample would have yielded equal daughter to parent ratio.

 At time (days)            Mass of sample

      0                                 100g

     5                                    50g

    10                                    25g

Every 5 days, the sample will split into half.

Therefore, 25g will remain after 10days.

explanation: magnetic pole, region at each end of a magnet where the external magnetic field is strongest. the south-seeking pole, or any pole similar to it, is called a south magnetic pole. unlike poles of different magnets attract each other; like poles repel each other.

pe = weightxheight = 2000x1000=2,000,000joules