List of top Physics Questions on Radioactivity

A radioactive isotope phosphorous-32 has an initial activity 10μCi and has half life of 14 days. What is the activity of the source after 42 days?

A radioactive sample has half-life of 3 years. The time required for the activity of the sample to reduce to $\frac{1}{5}$th of its initial value is about

A radio active material is reduced to 1/8 of its original amount in 3 days.
If 8×10^-3 kg of the material is left after 5 days the initial amount of the material is

A radioactive element 242 92 X emits two α-particles, one electron and two positrons. The product nucleus is represented by 234 P Y . The value of P is _______.

If a radioactive element having half-life of 30 min. is undergoing beta decay, the fraction of radioactive element remains undecayed after 90 min. will be

A radioactive nuclei X decays simultaneously to two nuclei Y and Z as:

t_½ is 12 minutes while t'_½ is 3 minutes. Find the time in which nuclei X decays 50%.

The minimum kinetic energy needed by an alpha particle to cause the nuclear reaction $^{16}_{7}\text{N} + ^{4}_{2}\text{He} \rightarrow ^{1}_{1}\text{H} + ^{19}_{8}\text{O}$ in a laboratory frame is n (in MeV). Assume that $^{16}_{7}\text{N}$ is at rest in the laboratory frame. The masses of $^{16}_{7}\text{N} , ^{4}_{2}\text{He} , ^{1}_{1}\text{H}\ \text{and}\ ^{19}_{8}\text{O}$ can be taken to be 16.006u,4.003u, 1.008u and 19.003u, respectively, where 1u=930MeVc⁻². The value of n is ________

The half life of a radioactive substance is 5 years. After x years, a given sample of the radioactive substance gets reduced to 6.25% of its initial value. The value of x is ______.

How many alpha and beta particles are emitted when Uranium ₉₂U²³⁸ decays to lead₈₂Pb²⁰⁶

The activity of a radioactive material is 6.4 × 10^-4 curie. Its half life is 5 days. The activity will become 5 × 10^-6 curie after

In a radioactive decay chain reaction, ${ }_{90}^{230} Th$ nucleus decays into ${ }_{84}^{214} Po$ nucleus. The ratio of the number of $\alpha$ to number of $\beta^{-}$particles emitted in this process is _____

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 log_e (no. of undecayed nuclei) Vs. time represents the reciprocal of mean life time (τ).
(D) Product of decay constant (λ) and half-life time (T_1/2) is not constant.
Choose the most appropriate answer from the options given below:

During $ẞ^{-}$ decay of a radioactive element there is an increase in its

A radio-active elements has half-life of 15 years. What is the fraction that will decay in 30 years?

B-122 has half life of 2 minutes experiment has to be done using Ba-122 and it take 10 minutes the setup the experiments if initially 80 gm of Ba-122 was taken how much Ba was left when experiment was started

A radioactive element forms its own isotopes after three consecutive disintegrations. The particles emitted are

For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is

When the light of frequency 2v₀ (where v₀ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is v₁ . When the frequency of the incident radiation is increased to 5v₀ , the maximum velocity of electrons emitted from the same plate is v₂ . The ratio of v₁ to v₂ is

Radioactive material 'A' has decay constant '8λ' and material 'B' has decay constant 'λ'. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be $\frac 1e$ ?

The half life of a radioactive isotope 'X' is 20 years. It decays to another element 'Y' which is stable. The two elements 'X' and 'Y' were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be

The half-life period of a radioactive element X is same as the mean lifetime of another radioactive element Y. Initially, both of them have the same number of atoms. Then

List of top Physics Questions on Radioactivity

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