MereTeacher

JEE • NEET • FOUNDATION

JEE · NEET Previous Year Question

$Half life of a radioactive element is 12.5 hour and its quantity is 256 g . After how much time its quantity will remain 1 g ?$

Topic: NEET PYQ

Answer: B. Full step-by-step solution below.

A $50 hrs$
B $100 hrs$
C $150 hrs$
D $200 hrs$

Correct answer: B

Solution

(b) \frac{N}{N _{0}} = (\frac{1}{2})^{n} n \to no of decays \frac{1}{256} = (\frac{1}{2})^{8} = (\frac{1}{2})^{n} ∴ n = 8 Time for 8 half life = 100 hours.

More Nuclei PYQs

$A radioactive nucleus can decay by two different processes. The half lives of the first and second decay processes are\dots$
$α -decay of a parent nucleus X results in a daughter nucleus Y. If m_{x}, m_{y} and m_{a} are the mas\dots$
$The activity of a radioactive sample is measured as N_{0} counts per minute at t = 0 and N_{0} / e counts per minute at\dots$
$A nucleus with mass number 240 breaks into two fragments each of mass number 120, the binding energy per nucleon of unfragmented n\dots$
$A nucleus ruptures into two nuclear parts, which have their velocity ratio equal to 2 : 1 . What will be the ratio of their\dots$