Galvanometer Half Deflection Method Viva Questions
Galvanometer Half-Deflection Method Viva Questions
This page presents viva questions for the experiment to determine the resistance of a galvanometer by the half-deflection method and to find its figure of merit. These questions follow CBSE physics practical standards, so students can answer confidently during viva voce.
Basic Viva Questions
Q1. What is a galvanometer?
A galvanometer detects and measures small electric currents.
Q2. What is meant by the half-deflection method?
In this method, we connect a shunt resistance so the galvanometer deflection becomes half.
Q3. Why do we use the half-deflection method?
Because this method helps us find the internal resistance of the galvanometer accurately.
Q4. What is the figure of merit of a galvanometer?
The figure of merit gives the current required for one division deflection.
Q5. What is the SI unit of figure of merit?
The SI unit is ampere per division.
Procedure-Related Viva Questions
Q6. How do you obtain the initial deflection?
First, adjust the series resistance until the galvanometer shows a steady deflection.
Q7. What do you do after obtaining the initial deflection?
Next, connect a suitable shunt resistance across the galvanometer.
Q8. Why do you adjust the shunt resistance?
So the galvanometer deflection reduces exactly to half.
Q9. Why should the battery emf remain constant?
Because a changing emf changes the current and affects accuracy.
Q10. Why must all connections remain tight and clean?
Because loose connections add extra resistance and cause errors.
Conceptual Viva Questions
Q11. Why does half deflection occur when shunt resistance equals galvanometer resistance?
Because the current divides equally between the galvanometer and the shunt.
Q12. How do you determine the resistance of the galvanometer?
At half deflection, the shunt resistance value equals the galvanometer resistance.
Q13. How do you calculate the figure of merit?
Divide the current through the galvanometer by the number of scale divisions.
Q14. What does a smaller figure of merit indicate?
Therefore, a smaller figure of merit indicates higher sensitivity.
Q15. Why should deflection remain within scale limits?
Because excessive deflection can damage the galvanometer.
Application-Based Viva Questions
Q16. Why is galvanometer resistance important?
Because it helps convert a galvanometer into an ammeter or a voltmeter.
Q17. Where do we use the concept of figure of merit?
Thus, we use it while designing sensitive electrical measuring instruments.
Q18. Can this method work for any galvanometer?
Yes, provided the galvanometer shows a linear relation between current and deflection.
Q19. What happens if the shunt resistance is very large?
Then the deflection does not reduce to half.
Q20. Why do we take repeated readings?
Because repeated readings reduce random errors and improve accuracy.
Error Analysis Viva Questions
Q21. What types of errors occur in this experiment?
Generally, systematic errors, random errors, and observational errors occur.
Q22. What causes systematic error in this experiment?
Because inaccurate resistance values and internal variations affect readings.
Q23. What are random errors?
Random errors occur due to small fluctuations in deflection readings.
Q24. What are observational errors?
Usually, parallax while reading the scale causes observational errors.
Q25. How can you reduce experimental errors?
So, take multiple readings, maintain clean connections, and keep conditions stable.
Quick Examiner-Style Viva Questions
- SI unit of resistance: Ohm (Ω)
- Shunt resistance is connected: in parallel
- Half deflection means: galvanometer current becomes half
- High sensitivity means: small current gives large deflection
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