JEE Main 2014 · 12 Apr · Shift 1 · Physics Q27

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PhysicsSingle correct+4 / -1Question 27 of 90

A piece of bone of an animal from a ruin is found to have $^{14}$ C activity of 12 disintegrations per minute per gm of its carbon content. The $^{14}$ C activity of a living animal is 16 disintegrations per minute per gm. How long ago nearly did the animal die ? (Given half life of $^{14}$ C is $t_{1/2}=5760$ years)

1672 years

2391 years

3291 years

4453 years

Answer and worked solution

Official answer: B

$t=\frac{t_{1/2}}{\ln2}\ln\frac{16}{12}=\frac{5760}{0.693}\times0.2877\approx2391\text{ years}.$

Topics:Radioactive decay

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JEE Main 2014 · 12 Apr · Shift 1, Physics question 27