Define Radioactivity

Collegedunia Team logo

Collegedunia Team

Content Curator

Radioactivity is the act of emitting radiation spontaneously. Radioactivity occurs through an atomic nucleus that is unstable. It "wants" to give up some energy to shift to a more stable configuration.

In Physics. Radioactivity is a nuclear phenomenon of spontaneous emission of α (Alpha) or β (Beta) or γ (Gamma) radiations from the nucleus of atoms during their decay. Uranium and Plutonium exhibit radioactivity and are examples of a radioactive substance.

Radioactivity

Radioactivity

Also read:

CBSE CLASS XII Related Questions

  • 1.
    Photoemission of electrons occurs from a metal (\( \phi_0 = 1.96 \, \text{eV} \)) when light of frequency \( 6.4 \times 10^{14} \, \text{Hz} \) is incident on it. Calculate: Energy of a photon in the incident light, The maximum kinetic energy of the emitted electrons, and The stopping potential.


      • 2.
        The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

          • \( \frac{q}{4 \pi \epsilon_0 l^2} \) pointing along MA
          • \( \frac{q}{\pi \epsilon_0 l^2} \) pointing along AM
          • \( \frac{q}{2 \pi \epsilon_0 l^2} \) pointing along AM
          • Zero

        • 3.
          A tank is filled with a liquid to a height of \( 12.5 \, \text{m} \). The apparent depth of a needle lying at the bottom of the tank is measured to be \( 9.0 \, \text{m} \). Calculate the speed of light in the liquid.


            • 4.
              What is displacement current (\( i_d \))? Considering the case of charging of a capacitor, show that \( i_d = \varepsilon_0 \frac{d\Phi_E}{dt} \). What is the value of \( i_d \) for a conductor across which a constant voltage is applied?


                • 5.
                  If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.


                    • 6.
                      Two parallel plate capacitors X and Y are connected in series to a 6 V battery. They have the same plate area and same plate separation but capacitor X has air between its plates, whereas capacitor Y contains a material of dielectric constant 4. Calculate the capacitances of X and Y, if the equivalent capacitance of the combination of X and Y is \( 4 \, \mu\text{F} \). Calculate the potential difference across the plates of X and Y.

                        CBSE CLASS XII Previous Year Papers

                        Comments


                        No Comments To Show