NEET Physics Electromagnetic Induction : Multiple Choice Previous Years Questions MCQs 3

TL;DR

This video explains the concepts of electromagnetic induction and potential difference in circuits, with examples and detailed calculations.

Transcript

hello friends this video on neat electromagnetic induction is brought to you by example.com no more fear from exact question number 19 in the circuit of figure the bulb will become suddenly bright if contact is made or broken contact is made contact is broken none of the above now see if the contact is made that means if you complete the now when t... Read More

Key Insights

• 🤳 When the contact is broken in a circuit with an inductor, the bulb becomes brighter due to the self-induced current.
• ❤️‍🩹 The potential difference between the two ends of a rotating rod can be calculated by integrating the emf equation.
• 🚄 The reading of a millivolt meter on a railway track depends on the speed of the train and the magnetic field.
• 🏑 The resistance of a circuit with a changing magnetic field can be determined using the growth equation for current.

Questions & Answers

Q: Why does the bulb become brighter when the contact is broken in a circuit with an inductor?

When the contact is broken, the sudden change in current causes a self-induced current in the circuit due to the inductor. This additional current causes the bulb to become brighter momentarily.

Q: How can the potential difference between the two ends of a rotating rod be calculated?

By considering a small element along the rod and integrating the expression for induced emf, the potential difference between the center and one end of the rod can be calculated as (b * omega * l^2) / 8.

Q: What will be the reading of a millivolt meter when a train travels on a railway track at a high speed?

The reading of the millivolt meter will be 1 millivolt when the train moves at a speed of 180 kilometers per hour, as it generates a motional emf due to the magnetic field.

Q: How can the resistance of a circuit with a changing magnetic field be determined?

By analyzing the change in magnetic field and using the growth equation for current, the resistance of the circuit can be calculated as -l / (t * ln(1 - 0.20)), which equals 160 ohms in this case.

Summary & Key Takeaways

• The video explains how the brightness of a bulb in a circuit changes when the contact is made or broken, due to the presence of an inductor.

• It demonstrates the calculation of potential difference in a rotating rod with a uniform magnetic field.

• The video also covers the concept of induced current in a moving conducting loop and the reading of a millivolt meter when a train moves on a railway track.

• Additionally, it explains the calculation of resistance in a circuit with a changing magnetic field and the calculation of magnetic energy stored in a cube inside a circular loop.