Question 219: Atoms & Nuclei

Question

Following statements related to radioactivity are given below :
(A) Radioactivity is a random and spontaneous process and is dependent on physical and chemical conditions.
(B) The number of un-decayed nuclei in the radioactive sample decays exponentially with time.
(C) Slope of the graph of loge (no. of undecayed nuclei) Vs. time represents the reciprocal of mean life time ($$	au$$).
(D) Product of decay constant ($$\lambda$$) and half-life time (T1/2) is not constant.
Choose the most appropriate answer from the options given below :

Accepted Answer

Radioactive decay is a random and spontaneous process it depends on unbalancing of nucleus.
$$N = {N_0}{e^{ - \lambda t}}$$ ..... (B)
$$\ln N =  - \lambda t + \ln {N_0}$$
So, slope $$ =  - \lambda $$ ..... (C)
$${t_{1/2}} = {{\ln 2} \over \lambda }$$
So $${t_{1/2}} 	imes \lambda  = \ln 2 = $$ Constant

Answer

(A) and (B) only

Answer

(B) and (D) only

Answer

(B) and (C) only

Answer

(C) and (D) only

Atoms & Nuclei

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