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Number of nuclei of a radioactive substa...

Number of nuclei of a radioactive substance at time t=0 are 2000 and 1800 at time t=2 s. number of nuclei left after t=6s is

A

1442

B

1554

C

1652

D

1458

Text Solution

Verified by Experts

The correct Answer is:
C
Activity, `A=A_(0)e^(-lamdat)`
`therefore 975=9750e^(-lamdaxx5)`
`(1)/(10)=e^(-lamdaxx5)`
Taking logarithm on both sides, we have
`-log_(e)10=-5lamda`
`-2.3026=-5lamda`
`lamda=(2.3026)/(5)=0.461" min"^(-1)`
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MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS-ATOMS, MOLECULES AND NUCLEI -Exercise 1 (TOPICAL PROBLEMS)
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  7. A sample of a radioactive element has a mass of 10 g at an instant t=0...

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  9. Two radioactive materials X(1) and X(2) have decay constants 5 lambda ...

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  10. Activity of a radioactive sample decreases to (1/3)rd of its original ...

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  12. Which of the following cannot be emitted by radioactive substances dur...

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  13. The ratio of half-life times of two elements A and B is (T(A))/(T(B))....

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