An electric lamp of 100 Ohms, a toaster of resistance 50 Ohms, and a water filter of resistance 500 Ohms are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current?

Given parameters:

  • Resistance of electric lamp (R1) = 100 Ω
  • Resistance of toaster (R2) = 50 Ω
  • Resistance of water filter (R3) = 500 Ω
  • A potential difference of the source (V) = 220 V

To find:

  • The flow of electric current through the electric iron.
  • Resistance of an electric iron

The three resistors are connected in parallel as shown – 

All 3 resistances are connected in parallel

Solution:
1) The total resistance (R) can be calculated by – 

1/R = 1/R1 + 1/R2 + 1/R3

1/R = 1/100  + 1/50 + 1/500

1/R = (5 + 10 + 1)/500

1/R = 16/500

Total Resistance (R) = 500/16 = 31.25 Ω

2) According to Ohm’s law, the current through a conductor is directly proportional to the voltage across two points of a conductor.

V = IR

Where R is constant called resistance.

R = V/I

I = 220 × (16/500)

I = 7.04 A

Therefore, the resistance of the electric iron is 31.25 Ω and the current flowing through it is 7.04 A.


Related Questions

  1. What is the necessary condition for a conductor to obey Ohm's Law?
  2. How do you find the resistance in Ohm's law?
  3. What Is Effective Resistance?
  4. Why is the curve representing Ohm's law linear?
  5. What Is Ohm's Law Graph?
  6. State Ohms law. How can it be verified experimentally?
  7. What are the limitations of Ohm's Law?
  8. What are the 3 forms of Ohm's law
  9. Why Do We Use Ohm's Law?
  10. State Ohms Law. Express It Mathematically. Define Si Unit Of Resistance.
  11. Draw a circuit diagram to verify ohm’s law.
  12. What Is The Basic Principle Of Ohm's Law?
  13. What are the applications of ohm's law used in daily life?
  14. Is resistance constant in Ohm's law?
  15. Obtain the equation J = σE of Ohm's law on the basis of drift velocity

Read More:

CBSE CLASS XII Related Questions

  • 1.
    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 $\frac{1}{4\pi\epsilon_0} \frac{(q_1 + q_2) (r_1 + r_2)}{r_1 r_2}$

    • 2.
      Capacitors are manufactured with certain standard capacitances and working voltages. However, these standard values may not be the ones that are actually needed in a particular application. Two or more capacitors can be grouped in series or in parallel to achieve desired capacitance and voltage. When connected in series, the total capacitance decreases while the voltage rating increases, whereas in parallel connections, the total capacitance increases and maintains the same voltage rating. A capacitor stores energy in the electric field between its plates and stored energy is proportional to the square of the voltage and capacitance $U = \frac{1}{2}CV^2$, where symbols have their usual meanings.
      Two capacitors, one of $3 \ \mu$F and the other of $6 \ \mu$F, are connected in series in the circuit as shown in the figure, for a long time. }


        • 3.
          Write two advantages of reflecting telescope over refracting telescope.


            • 4.
              This ‘average velocity’ is found be few mm/s for currents in range of a few amperes. How then is current established almost the instant a circuit is closed ?


                • 5.
                  Consider the nuclear reaction \( X \to Y + Z \). Let \( M_x \), \( M_y \), and \( M_z \) be the masses of the three nuclei X, Y, and Z respectively. Then which of the following relations hold true?

                    • \( (M_x - M_z)<M_y \)
                    • \( (M_x - M_y)<M_z \)
                    • \( M_x>(M_y + M_z) \)
                    • \( M_x<(M_y + M_z) \)

                  • 6.
                    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.

                      CBSE CLASS XII Previous Year Papers

                      Comments


                      No Comments To Show