What is echo?

Jasmine Grover logo

Jasmine Grover

Education Journalist | Study Abroad Lead

In acoustics, an echo is a reflection of sound waves off a surface back to the listener after a delay of a few seconds or more.

  • Echo is the reflection of sound reaching the listener after some time.
  • It often creates a repetitive, distorted, and sometimes amplified effect.
  • It can occur naturally in environments with hard surfaces or be deliberately created for artistic or communication purposes using specialized equipment.

Also Check:

CBSE CLASS XII Related Questions

  • 1.
    A long solenoid of length \( L \) and radius \( r_1 \) having \( N_1 \) turns is surrounded symmetrically by a coil of radius \( r_2 \, (r_2>r_1) \) having \( N_2 \) turns (\( N_2 \ll N_1 \)) around its mid-point. Derive an expression for the mutual inductance of solenoid and coil. Is \( M_{12} = M_{21} \) valid in this case?


      • 2.
        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?


          • 3.
            Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.


              • 4.
                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.


                  • 5.
                    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

                    • 6.
                      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.

                        CBSE CLASS XII Previous Year Papers

                        Comments


                        No Comments To Show