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

If the resistance of a conductor is increased to three times, then the current will be: (voltage V remains constant)

This question was previously asked in
RRB NTPC 2024 Undergraduate CBT 1 Question Paper (29-Aug-2025) (Shift 1)
The correct answer is

one third

Understanding Resistance and Current Relationship

This question explores the relationship between electrical resistance, current, and voltage in a conductor. The key principle governing this relationship is Ohm's Law.

Applying Ohm's Law

Ohm's Law states that the voltage (\(V\)) across a conductor is directly proportional to the current (\(I\)) flowing through it, provided the temperature and other physical conditions remain unchanged. Mathematically, it is expressed as:

\( V = IR \)

Where:

  • \(V\) is the voltage across the conductor (in Volts)
  • \(I\) is the current flowing through the conductor (in Amperes)
  • \(R\) is the resistance of the conductor (in Ohms)

In this problem, we are given that the voltage (\(V\)) remains constant.

Calculating the Impact of Increased Resistance

Let's denote the initial resistance as \(R_1\) and the initial current as \(I_1\). According to Ohm's Law:

\( V = I_1 R_1 \)

The problem states that the resistance is increased to three times its original value. Let the new resistance be \(R_2\). Therefore:

\( R_2 = 3 R_1 \)

Let the new current flowing through the conductor be \(I_2\). Since the voltage (\(V\)) remains constant, we can write the equation for the new state:

\( V = I_2 R_2 \)

Because the voltage \(V\) is constant in both situations, we can equate the two expressions:

\( I_1 R_1 = I_2 R_2 \)

Now, substitute the expression for \(R_2\) (\(R_2 = 3 R_1\)) into the equation:

\( I_1 R_1 = I_2 (3 R_1) \)

To find the new current (\(I_2\)), we can rearrange the equation. Assuming the initial resistance \(R_1\) is not zero, we can divide both sides by \(R_1\):

\( I_1 = 3 I_2 \)

Finally, solve for \(I_2\):

\( I_2 = \frac{I_1}{3} \)

Conclusion

The calculation shows that the new current (\(I_2\)) is one-third of the original current (\(I_1\)). Therefore, if the resistance of a conductor is increased to three times while the voltage remains constant, the current will become one third.

Was this answer helpful?

Similar Questions

  1. Which of the following household items does NOT use the heating effect of current?

  2. The magnetic field produced by a current-carrying wire at a given point depends on which of the following factors?

  3. Which of the following statements is/are correct?

    Statements:

    I) A current carrying conductor acts like a magnet.

    II) Moving electrons perpendicular to the magnetic field do not experience any force.

  4. Which physical quantity represents the rate at which electric energy is dissipated or consumed in an electric circuit?

  5. In Fleming's left hand rule, which physical quantity is represented by the middle finger?

  6. The work done in moving a charge +Q across two points having a potential difference K is:

  7. Which of the folloewing devices does NOT make use of current carrying conductor in a magnetic field ?

  8. The equivalent resistance of the two resistors of resistance R ohm each connected in series is_______?

  9. Which of the following statements is/are correct?

    Statements:

    1) Electromagnet is a device used to convert magnetic field into electrical energy.

    II) Electromagnet is a device used to convert mechanical energy into magnetic energy.

  10. In a closed circuit, if 100 coulomb charges flow for 50 sec, then the current drawn in the circuit is ............


Important Questions from Electricity

  1. 'Net metering' is sometimes seen in the news in the context of promoting the

  2. The complete form of 'IC' in electronics is
  3. Which of the following household items does NOT use the heating effect of current?

  4. The magnetic field produced by a current-carrying wire at a given point depends on which of the following factors?

  5. Which of the following statements is/are correct?

    Statements:

    I) A current carrying conductor acts like a magnet.

    II) Moving electrons perpendicular to the magnetic field do not experience any force.

Need Expert Advice?
Upcoming Exams
RRB Technician
October 06, 2026
RRB JE
October 27, 2026
RRB ALP
November 03, 2026
Test Series
RRB ALP img
Railways
RRB ALP 2026 Mock Test series
1035 Tests 1 Tests Free
1167 Attempts
4.3(242)
English, Hindi

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