A10 pound block of lead-210 has a half-life of 22 years. what percentage of the block still contains lead-210 after 60 years?
1.5%
15%
77%
27%

The percentage of the block contains 15% after 60 years.

Explanation:

Step 1: Formula for half-life time

To calculate the half-life time we will use the following formula:

At = A0 * 1/2 ^(x/t)

With At = the quantity after a time t

A0 = The quantity at time t = 0 (start)

x = time in this case = 60 years

t= half-life time = 22 years

Step 2: Calculate the percentage after 60 years

In this case: after 60 years the percentage will be

A0= 10 * 1/2 ^(60/22)

A0 = 1.5

A0 / At  = 1.5 /10 = 0.15

0.15 *100% = 15 %

The percentage of the block contains 15% after 60 years.

pla·gia·rism

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noun

the practice of taking someone else's work or ideas and passing them off as one's own.

explanation:

smooth muscle is composed of involuntary muscles found within the walls of organs and structures such as the esophagus, stomach, intestines, and blood vessels. those muscles push materials like food or blood through organs. unlike skeletal muscle, smooth muscle can never be under your control.