Radioactivity of a radioactive element remains 1/10 of the original radioactivity after 2.303 s.

Content Curator

$λ = \frac{2.303}{t}log_{10}\frac{a}{(a-x)}$

$λ = \frac{2.303}{2.303}log_{10}\frac{1}{(10)}=1$

$T = \frac{0.693}{λ}=0.693$

Radioactivity is the atomic property occurring due to reactions taking place in the atomic nucleus. In certain isotopes of a number of elements, radioactivity becomes unstable and disintegrates with the production of radiation and usually of an atom or atoms of other elements.

Also check:

Physics Guide Links
Class 12 Physics Notes	Difference between in physics	Physics Constants
Physics Practical	SI Units in Physics	Physics Formula
Derivations in Physics	Relation Between articles (Physics)	Physics

CBSE CLASS XII Related Questions

1.
A student sets up the circuit as shown in the figure to find the value of unknown resistance X and records a set of readings of the voltmeter and the ammeter by using the rheostat.
2.
Write two advantages of reflecting telescope over refracting telescope.
View Solution
3.
Read the following paragraph and answer the questions that follow.
A p-type or n-type semiconductor can be converted into a p-n junction by doping it with suitable impurity. The motion of majority charge carriers causes diffusion current across the junction while the barrier electric field causes motion of minority carriers for drift current. In case of unbiased diode, the diffusion and drift currents are equal. This equilibrium is disturbed by the biasing batteries. Diodes, therefore, allow currents in one direction. This property of diode is used in making rectifiers.
4.
A charged particle $+q$ in an electric field $\vec{E}$ experiences a force in the direction of the electric field. As a result, its kinetic energy changes. Similarly, the charged particle also experiences a force when it moves in a magnetic field $\vec{B}$. But this magnetic force is perpendicular to both velocity $\vec{v}$ of the charged particle and the magnetic field $\vec{B}$, so it cannot change the kinetic energy of the charged particle. Consider two charged particles 1 and 2 of masses $m$ and $\frac{m}{2}$ having charges $-q$ and $+2q$ respectively. They are accelerated from rest through the same potential difference $V$ and acquire kinetic energy $K_1$ and $K_2$. Then they enter in a region of uniform magnetic field $\vec{B}$ perpendicular to their velocities.
5.
Read the following paragraph and answer the questions that follow.
In an experiment with convex lens of focal length f, the screen is fixed at a distance D from the object. A student slowly moves the lens away from the object towards the screen and finds that she is able to form sharp image of the object for two positions of the lens. The distance between these two positions of the lens is d.
6.
Two air-filled capacitors of capacitances $C_1$ and $C_2$ are connected in parallel with a dc battery. After the capacitors are fully charged, a slab of dielectric constant K is inserted between the plates of each capacitor. How will the (i) charge on each capacitor and (ii) energy stored in the capacitor affected after the slab is introduced.
View Solution