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
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B. is ur answer I bieleve
Energy were released from the walnut, q = 1,673.6 J
<h3>Equation :</h3>
To find the energy using formula,
q = mcΔt
where,
q is charge
m is mass
c is specific heat of water
Δt is change in temperature
So, given
t₁ = 50°C
t₂ = 60°C
m = 40g
c = 4.184 J/g
Now putting the values known,
We get,
q = mc(t₂ - t₁)
q = 40g x 4.184 J/g x (60 - 50)
q = 167.36 J x 10
q = 1,673.6 J
<h3>What is heat energy?</h3>
Heat is the thermal energy that is transferred when two systems with different surface temperatures come into contact. Heat is denoted by the letters q or Q and is measured in Joules.
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