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प्रश्न
Obtain the expression for current sensitivity of moving coil galvanometer.
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उत्तर
The sensitivity (i.e. current sensitivity) of a galvanometer is defined as the angle of deflection per unit current flowing through it.
If dθ is change in the deflection produced by a small change in the current dI, sensitivity (S) of the galvanometer is given by
`S=(d theta)/(dI)`
The current I flowing through a moving coil galvanomet er is given by
`I=k/(nAB)theta` where θ is the angle of deflection , N is its turns, A is area, B is magnetic induction & k is the couple per unit twist.
`theta = (NAB)/k I`
`(d theta)/(dI)=(NAB)/k`
`S=(NAB)/k`
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संबंधित प्रश्न
Show that the current flowing through a moving coil galvanometer is directly proportional to the angle of deflection of coil.
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An ideal voltmeter has _______.
(A) low resistance
(b) high resistance
(C) infinite resistance
(D) zero resistance
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Increasing the current sensitivity of a galvanometer may not necessarily increase its voltage sensitivity. Explain, giving reason.
A rectangular coil of a moving coil galvanometer contains 100 turns, each having area
15 cm2. It is suspended in the radial magnetic field 0.03 T. The twist constant of suspension
fibre is 15 x 10-10 N-m/degree. Calculate the sensitivity of the moving coil galvanometer.
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A galvanometer has a resistance of 16Ω. It shows full scale deflection, when a current of 20 mA is passed through it. The only shunt resistance available is 0.06 which is not appropriate to convert a galvanometer into an ammeter. How much resistance should be connected in series with the coil of galvanometer, so that the range of ammeter is 8 A?
Define current sensitivity of a galvanometer.
Outline the necessary steps to convert a galvanometer of resistance RG into an ammeter of a given range ?
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What are the advantages of using soft iron as a core, instead of steel, in the coils of galvanometers?
Why are the pole pieces of a horseshoe magnet in a moving coil galvanometer made cylinder in shape?
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?
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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 AC voltage across a resistance can be measured using a ______.
The deflection in a moving coil galvanometer is ______.
In a moving coil galvanometer the deflection (Φ) on the scale by a pointer attached to the spring is ______.
A moving coil galvanometer can be converted into an ammeter by ______.
The coil of a moving coil galvanometer is wound over a metal frame in order to ______.
The current sensitivity of a galvanometer increase by 20%. If its resistance also increases by 25%, the voltage sensitivity will ______.
Assertion (A): On Increasing the current sensitivity of a galvanometer by increasing the number of turns may not necessarily increase its voltage sensitivity.
Reason (R): The resistance of the coil of the galvanometer increases on increasing the number of turns.
Select the most appropriate answer from the options given below:
A galvanometer having a coil resistance of 60 Ω shows full-scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents up to 5.0 amp by:
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The coil of galvanometer consists of 100 turns and effective area of 1 square cm. The restoring couple is 10-8 N-m/rad. The magnetic field between the pole pieces is 5T. The current sensitivity of this galvanometer will be ______.
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A galvanometer of resistance 100 Ω gives a full-scale deflection for a potential difference of 200 mV.
- What must be the resistance connected to convert the galvanometer into an ammeter of the range 0-200 mA?
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Current sensitivity of a galvanometer is defined as the:
Voltage sensitivity of a galvanometer is defined as the:
The figure of merit of a galvanometer is:
The current sensitivity of a moving coil galvanometer is given by:
The unit in which the current sensitivity of a galvanometer is expressed is:
The voltage sensitivity of a moving coil galvanometer, where G is the resistance of the galvanometer coil, is given by:
In the pivoted-coil (Weston) type galvanometer, the two hair springs:
The pointer used to read the deflection on the calibrated scale of a moving coil galvanometer is made of:
The non-magnetic frame of a moving coil galvanometer is made of aluminium, and its function is to provide:
A voltmeter is connected across a component:
In a circuit with a 3 V source and a 3 Ω resistor, the galvanometer \((R_G = 60\ \Omega)\) is converted into an ammeter using a shunt resistance \(r_s = 0.02\ \Omega\). The measured current is approximately:
A circuit consists of a 3 V source and a 3 Ω resistor. With an ideal ammeter of zero resistance inserted, the current in the circuit is:
