A teacher in his physics laboratory allotted an experiment to determine the resistance (G) of a galvanometer. Students took the observations for \(\frac 13\) deflection in the galvanometer. Which of the below is true for measuring value of G?
- \(\frac 13\) deflection method cannot be used for determining the resistance of the galvanometer.
- \(\frac 13\) deflection method can be used and in this case the G equals to twice the value of shunt resistance(s).
- \(\frac 13\) deflection method can be used and in this case, the G equals to three times the value of shunt resistance(s).
- \(\frac 13\) deflection method can be used and in this case the G value equals to the shunt resistance(s).
The Correct Option is B
Solution and Explanation
The circuit for the given situation is:
Since G and S are in parallel,
\(\frac i3 \times G = \frac {2i}{3} \times S\)
\(G = 2S\)
So, G equals twice the value of shunt resistance.
Hence, the correct option is (B): \(\frac 13\) deflection method can be used and in this case the G equals to twice the value of shunt resistance(s).
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Concepts Used:
Moving Charges and Magnetism
Moving charges generate an electric field and the rate of flow of charge is known as current. This is the basic concept in Electrostatics. Another important concept related to moving electric charges is the magnetic effect of current. Magnetism is caused by the current.
Magnetism:
- The relationship between a Moving Charge and Magnetism is that Magnetism is produced by the movement of charges.
- And Magnetism is a property that is displayed by Magnets and produced by moving charges, which results in objects being attracted or pushed away.
Magnetic Field:
Region in space around a magnet where the Magnet has its Magnetic effect is called the Magnetic field of the Magnet. Let us suppose that there is a point charge q (moving with a velocity v and, located at r at a given time t) in presence of both the electric field E (r) and the magnetic field B (r). The force on an electric charge q due to both of them can be written as,
F = q [ E (r) + v × B (r)] ≡ EElectric +Fmagnetic
This force was based on the extensive experiments of Ampere and others. It is called the Lorentz force.