After the 1st half-life 250 g of the radioactive material will be left.
<span>After the 2nd half-life 125 g of the radioactive material will be left. </span>
<span>After the 3rd half-life 62.5 g of the radioactive material will be left. </span>
<span>Therefore after 60 minutes, 3 half lives would have occurred. </span>
<span>Therefore the half-life = 60 / 3 = 20 minutes when 250 grams of the original material would have remained radioactive. </span>
<span>Therefore the answer is A) About 250 gram of the material decayed in 20 minutes.</span>
Ocean levels fluctuate daily as the sun, moon and earth interact. As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world's oceans to rise and fall. Since the earth is rotating while this is happening, at least two tides occur each day.
Answer:
the science, art, or practice of cultivating the soil, producing crops, and raising livestock and in varying degrees the preparation and marketing of the resulting products cleared the land to use it for agriculture.
Explanation:
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