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प्रश्न
A multirange current meter can be constructed by using a galvanometer circuit as shown in figure. We want a current meter that can measure 10 mA, 100 mA and 1A using a galvanometer of resistance 10 Ω and that prduces maximum deflection for current of 1mA. Find S1, S2 and S3 that have to be used
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उत्तर
A galvanometer can be converted into ammeter by connecting a very low resistance wire (shunt S) connected in parallel with galvanometer. The relationship is given by IgG = (I – Ig) S, where Ig is the range of galvanometer and G is the resistance of galvanometer.
For measuring `I_1 = 10 mA: I_G.G = (I_1 - I_G)(S_1 + S_2 + S_3)`
For measuring `I_2 = 100 mA: I_G(G + S_1) = (I_2 - I_G)(S_2 + S_3)`
For measuring `I_3 = 1 A: I_G(G + S_1 + S_2) = (I_3 - I_G)(S_3)`
Gives `S_1 = 1 Ω, S_2 = 0.1 Ω`
And `S_3 = 0.01 Ω`
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संबंधित प्रश्न
An ideal voltmeter has _______.
(A) low resistance
(b) high resistance
(C) infinite resistance
(D) zero resistance
Why is it necessary to introduce a cylindrical soft iron core inside the coil of a galvanometer?
Increasing the current sensitivity of a galvanometer may not necessarily increase its voltage sensitivity. Explain, giving reason.
Explain how moving coil galvanometer is converted into a voltmeter. Derive the necessary formula.
A moving coil galvanometer has a resistance of 25Ω and gives a full scale deflection for a current of 10mA. How will you convert it into a voltmeter having range 0 - 100 V?
Why does a galvanometer when connected in series with a capacitor show a momentary deflection, when it is being charged or discharged?
How does this observation lead to modifying the Ampere's circuital law?
Hence write the generalised expression of Ampere's law.
Define the current sensitivity of a galvanometer ?
Outline the necessary steps to convert a galvanometer of resistance RG into an ammeter of a given range ?
A moving coil galvanometer has a coil of resistance 59 Ω. It shows a full-scale deflection for a current of 50 mA. How will you convert it to an ammeter having a range of 0 to 3A?
A galvanometer coil has a resistance of 15 Ω and the metre shows full scale deflection for a current of 4 mA. How will you convert the metre into an ammeter of range 0 to 6 A?
The deflection in a moving coil galvanometer is ______.
The current sensitivity of a galvanometer is defined as ______.
In a moving coil galvanometer the deflection (Φ) on the scale by a pointer attached to the spring is ______.
A voltmeter of variable ranges 3 V, 15 V, 150 V is to be designed by connecting resistances R1, R2, R3 in series with a galvanometer of resistance G = 20 Ω, as shown in Fig. The galvanometer gives full pass through its coil for 1 mA current i.e. "gives full pass through it's coil for 1 mA current". Then, the resistances R1, R2 and R3 (in kilo ohms) should be, respectively:
When a galvanometer is shunted with a 4 Ω resistance, the deflection is reduced to one-fifth. If the galvanometer is further shunted with a 2 Ω wire. The further reduction (find the ratio of decrease in current to the previous current) in the deflection will be (the main current remains the same)
A galvanometer coil bas 500 turns and each tum has an average area of 3 × 10-4 m2. If a torque of 1.5 Nm is required to keep this coil parallel to a magnetic field when a current of 0.5 A is flowing through it, the strength of the field (in T) is ______.
How is current sensitivity increased?
To convert a moving coil galvanometer into an ammeter we need to connect a ______.
