All Exams Test series for 1 year @ ₹349 only
Question

Three wires of resistance 3 ohm, 6 ohm and 9 ohm are connected in a parallel. What will be the total resistance of the circuit?

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper PDF (31-Jan-2021) (Shift 1)
The correct answer is

$\frac{18}{11}$ohms 

Parallel Resistance Calculation for Three Wires

To find the total resistance ($R_{total}$) of resistors connected in parallel, we use the formula:

$ \frac{1}{R_{total}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} $

Given the resistances:

  • $R_1 = 3 \Omega$
  • $R_2 = 6 \Omega$
  • $R_3 = 9 \Omega$

Substitute these values into the formula:

$ \frac{1}{R_{total}} = \frac{1}{3} + \frac{1}{6} + \frac{1}{9} $

To add these fractions, find a common denominator, which is 18:

$ \frac{1}{R_{total}} = \frac{1 \times 6}{3 \times 6} + \frac{1 \times 3}{6 \times 3} + \frac{1 \times 2}{9 \times 2} $ $ \frac{1}{R_{total}} = \frac{6}{18} + \frac{3}{18} + \frac{2}{18} $

Add the numerators:

$ \frac{1}{R_{total}} = \frac{6 + 3 + 2}{18} $ $ \frac{1}{R_{total}} = \frac{11}{18} $

Finally, invert the result to find the total resistance ($R_{total}$):

$ R_{total} = \frac{18}{11} \Omega $

Therefore, the total resistance of the circuit is $\frac{18}{11}$ ohms.

Was this answer helpful?

Similar Questions

  1. Which of the following devices is used to convert alternating current into direct current?
  2. According to Joule's law of heating, heat produced in a resistor is expressed by which relation?

  3. Electrical conductors are materials that possess which of the following properties?

  4. What change occurs in the amount of heat produced when the electric current in a conductor is doubled?

  5. When considering the dimensions of electric charge, which fundamental units must be combined to express it in terms of SI base quantities?

  6. Which one is not a good conductor of electricity?
  7. What is the SI unit of electric charge?

  8. Which of the following is a conductor of electric charge?

  9. If you measure the amount of electric charge flowing in a circuit, which SI unit would you use to record the result?

  10. If the resistance of a circuit is doubled, the current flowing through the circuit (keeping the voltage the same) will _____.
    A.increase by half
    B.decrease by half
    C.remain the same
    D.become zero


Important Questions from Current Electricity

  1. Which of the following is a bad conductor of electricity?

  2. In general, in an alternating current circuit

  3. The laws of electromagnetic induction have been used in the construction of a

  4. A 220 volt and 100 watt bulb is connected to a 110 volt source. The power consumption by the bulb is

  5. Which of the following statement is correct?

    I. 1 kWh = 3.6 × 10 6J.

    II. The SI unit of electric current is the ampere.

Need Expert Advice?
Upcoming Exams
RRB ALP
November 03, 2026
Test Series
RRB NTPC img
Railways
RRB NTPC Under Graduate 2026 New Mock Test Series
1612 Tests 1 Tests Free
1020 Attempts
4.3(516)
English, Hindi, Telugu +7 More
More Questions from RRB NTPC

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App