Write a short note on static electricity.

Static electricity refers to the imbalance of electric charges on the surface or between or within a material.

  • When an object is negatively charged, the other one becomes positively charged when they are closer. The constant rubbing of these two objects creates an electron imbalance and a buildup of self-produced current produces static electricity.
  • This is observed in both insulators and conductor. For instance, sticking of hair to the wool of a hat is a result of this.
  • This phenomenon is more common in the dry season as moisture prevents electron transfer.

Related Questions

  1. What Are Two Kinds Of Electricity?
  2. Can rubbing cause static electricity
  3. Where do we use static electricity in everyday life?
  4. What is balance point in potentiometer?
  5. What is the major difference between static electricity and current electricity?
  6. How is potential gradient measured?

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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.
        Consider a cylindrical conductor of length \( l \) and area of cross-section \( A \). Current \( I \) is maintained in the conductor and electrons drift with velocity \( \vec{v}_d \, (|\vec{v}_d| = \frac{eE}{m} \tau) \), where symbols have their usual meanings. Show that the conductivity of the material of the conductor is given by \[ \sigma = \frac{n e^2 \tau}{m}. \]


          • 3.
            An astronomical telescope consists of two converging lenses. One of them of large aperture and large focal length is called objective lens and the other one, of smaller focal length and smaller aperture is called the eyepiece. It is used to see distant objects which are not seen clearly with naked eyes. The image formed by the objective lens acts as an object for the eyepiece and the final image produced by the eyepiece is magnified.


              • 4.
                An electric field $\vec{E}$ is established across the ends of a cylindrical conductor of length L and area of cross-section A. Discuss how electrons attain an average velocity, independent of time. Hence, obtain a relation between current in the conductor and this ‘average velocity’ of electrons.


                  • 5.
                    Two metal spheres of radii $r_1$ and $r_2$ ($> r_1$) having charges $q_1$ and $q_2$ respectively kept in air, are brought in contact. Which of the following statements is not correct ?

                      • The total charge of the two spheres is conserved.
                      • Both spheres attain the same potential.
                      • The final potential of the system equals $\frac{1}{4\pi\epsilon_0} \frac{(q_1 + q_2)}{(r_1 + r_2)}$
                      • The final potential of the system equals $\frac{1}{4\pi\epsilon_0} \frac{(q_1 + q_2) (r_1 + r_2)}{r_1 r_2}$

                    • 6.
                      The resistance of a metal wire at \( 20^\circ \text{C} \) is \( 1.05 \, \Omega \) and at \( 100^\circ \text{C} \) is \( 1.38 \, \Omega \). Determine the temperature coefficient of resistivity of this metal.

                        CBSE CLASS XII Previous Year Papers

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