From the calculations, the half life of the material is 6.5 days.
<h3>What is radioactivity?</h3>
The term radioactivity has to do with the spontaneous disintegration of a specie.
Uisng the formula;
N=Noe^-kt
N= amount at time t = 0.135 Ci or 4.995 ×10^9 Bq
No = amount initially present = 1.75 x 10^12 Bq
k = rate constant = ?
t = time taken = 55 days
Hence;
4.995 ×10^9 = 1.75 x 10^12e^-55k
4.995 ×10^9/1.75 x 10^12 = e^-55k
2.85 * 10^-3 = e^-55k
ln2.85 * 10^-3 = -55k
k = ln2.85 * 10^-3/-55
k = 0.1066 day-1
Half life = 0.693/ 0.1066 day-1
= 6.5 days
Learn more about radioactivity:brainly.com/question/1770619
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When the body senses foreign substances (called antigens), the immune system works to recognize the antigens and get rid of them. B lymphocytes are triggered to make antibodies (also called immunoglobulins). These proteins lock onto specific antigens.
Answer:
Rachel needs 0.52 kg of fertilizer.
Explanation:
Since the surface is a <em>square</em> of 10 ft of size its area is A = 10 ft x 10 ft = 1.0 x 10² ft². <em>One third</em> of that space is devoted to tomatoes (<em>"space is divided equally among tomatoes, lettuce, and strawberries"</em>), that is, 1/3 x 100 ft² = 33 ft².
We calculate the kilograms of fertilizer required we need to know 2 equivalences:
1 ac = 43,560 ft²
1 lb = 0.4535 kg
Then, we can use proportions to find out the amount of fertilizer used:
Answer:
Fossil fuel power plants burn coal or oil to create heat which is in turn used to generate steam to drive turbines which generate electricity.
Explanation:
Fossil fuels are used in power plants to make steam. Steam drives turbines which coupled to generator produce electrical energy. Electrical power is used in all industries, domestic used where energy is needed.
petroleum products like oil, gas are used in motor vehicles, ships, airplanes. They burn and give the power for transport.
Fossil fuels are burned under different conditions in engines, boilers, etc which produce heat energy and then converted into mechanical energy.
gas and oil are used to heat homes.
