What is the principle of rheostat?

A rheostat works on the principle of Ohm’s law. Ohm’s law states that the current in a circuit is inversely proportional to the resistance at the given temperature.


Related Questions

  1. What Is The Formula Of Ammeter?
  2. What is the necessary condition for a conductor to obey Ohm's Law?
  3. Why is the series arrangement not used for domestic circuits?
  4. Define: 1 volt, Potential difference
  5. The resistance R= V/I, where V=100 ± 5.0V and I = 10 ± 0.2A. What is the total error in R?
  6. Draw a circuit diagram to verify ohm’s law.
  7. Is resistance constant in Ohm's law?
  8. What are the applications of ohm's law used in daily life?
  9. State And Explain Joules Law Of Heating.
  10. Why is the curve representing Ohm's law linear?
  11. What are ohmic and non-ohmic devices? Give examples.
  12. Obtain the equation J = σE of Ohm's law on the basis of drift velocity
  13. Find the current through a resistance 2 ohm if the voltage across the resistance is 6 V.
  14. A small bulb has a resistance of 2 ohms when it is cold. It draws 0.4-ampere current from a source of4V and then starts glowing. Calculate the resistance when it is glowing
  15. Why Do We Use Ohm's Law?

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CBSE CLASS XII Related Questions

  • 1.
    Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

      • attract with a force \( \frac{F}{2} \)
      • repel with a force \( \frac{F}{2} \)
      • repel with a force \( F \)
      • attract with a force \( F \)

    • 2.
      Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –

        • \((P_1+P_2)\)
        • \(\dfrac{P_1+P_2}{2}\)
        • \(\dfrac{P_1P_2}{2(P_1+P_2)}\)
        • \(\dfrac{P_1P_2}{4(P_1+P_2)}\)

      • 3.
        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.


          • 4.
            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.


              • 5.
                A light copper ring is freely suspended by a light string. A bar magnet is held horizontally with its length along the axis of the ring. The magnet is moved towards the ring with its N pole facing the loop. What will happen to the ring and its position? Explain.


                  • 6.
                    Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.

                      • Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
                      • Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
                      • Assertion (A) is true, but Reason (R) is false.
                      • Both Assertion (A) and Reason (R) are false.
                    CBSE CLASS XII Previous Year Papers

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