Advertisements
Advertisements
Question
The combined resistance of a galvanometer of resistance 500Ω and its shunt is 21Ω. Calculate the value of shunt.
Advertisements
Solution
Here, G = 500Ω and Req = 21Ω
`1/R_(eq)=1/G+1/S`
`therefore 1/S=1/R_(eq)-1/G=(G-R_(eq))/(GxxR_(eq)`
`therefore S=(GxxR_(eq))/(G-R_(eq)`
`therefore S=(500xx21)/(500-21)=10500/479`
`therefore S= 21.92 Omega`
APPEARS IN
RELATED QUESTIONS
The combined resistance of a galvanometer of resistance 500Ω and its shunt is 21Ω. Calculate the value of shunt.
A rectangular coil of a moving coil galvanometer contains 50 turns each having area 12 cm2 . It is suspended in radial magnetic field 0.025 Wb/m2 by a fibre of twist constant 15 x10-10 Nm/degree. Calculate the sensitivity of the moving coil galvanometer.
Show that the current flowing through a moving coil galvanometer is directly proportional to the angle of deflection of coil.
Why does a galvanometer show a momentary deflection at the time of charging or discharging a capacitor? Write the necessary expression to explain this observation.
A galvanometer of resistance G is converted into a voltmeter to measure upto V volts by connecting a resistance R1 in series with the coil. If a resistance R2 is connected in series with it, then it can measures upto V/2 volts. Find the resistance, in terms of R1 and R2, required to be connected to convert it into a voltmeter that can read upto 2 V. Also find the resistance G of the galvanometer in terms of R1 and R2
Draw a labelled diagram of a moving coil galvanometer. Describe briefly its principle and working.
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.
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?
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?
Why is it necessary to introduce a radial magnetic field inside the coil of a galvanometer?
Can a galvanometer as such be used for measuring the current? Explain.
How will you convert a moving coil galvanometer into a voltmeter?
With the help of a neat and labelled diagram, explain the principle and working of a moving coil galvanometer ?
Define the current sensitivity of a galvanometer ?
Write current sensitivity of a galvanomete S.I. unit.
Figure shows two circuits each having a galvanometer and a battery of 3V.
When the galvanometers in each arrangement do not show any deflection, obtain the ratio R1/R2.
In the meter bridge experiment, balance point was observed at J with AJ = l.
(i) The values of R and X were doubled and then interchanged. What would be the new position of balance point?
(ii) If the galvanometer and battery are interchanged at the balance position, how will the alance point get affected?
What are the advantages of using soft iron as a core, instead of steel, in the coils of galvanometers?
A coil of radius 10 cm and resistance 40 Ω has 1000 turns. It is placed with its plane vertical and its axis parallel to the magnetic meridian. The coil is connected to a galvanometer and is rotated about the vertical diameter through an angle of 180°. Find the charge which flows through the galvanometer if the horizontal component of the earth's magnetic field is BH = 3.0 × 10−5 T.
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?
State how a moving coil galvanometer can be converted into an ammeter.
Explain the significance of a radial magnetic field when a current-carrying coil is kept in it.
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 current sensitivity of a galvanometer is defined as ______.
A moving coil galvanometer can be converted into an ammeter by ______.
In an ammeter 0.5% of main current passes through galvanometer; If resistance of galvanometer is G, the resistance of ammeter will be.
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 ______.
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
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:
Explain in brief the basic construction of a moving-coil table galvanometer whit a neat labelled diagram.
A resistance of 3Ω is connected in parallel to a galvanometer of resistance 297Ω. Find the fraction of current passing through the galvanometer.
A moving coil galvanometer of resistance 55 Ω produces a full scale deflection for a current of 250 mA. How will you convert it into an ammeter with a range of 0 - 3A?
To convert a moving coil galvanometer into an ammeter we need to connect a ______.
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?
- Determine resistance of the ammeter.
A sensitive electromagnetic instrument used to detect and measure small electric currents (of the order of microamperes to milliamperes) by measuring the deflection of a current-carrying coil placed in a uniform magnetic field is called a:
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:
The figure of merit k of a galvanometer is given by:
The use of a radial magnetic field, in which \(\sin\theta = 1\) at all positions, produces a galvanometer scale deflection that is:
At equilibrium, the deflecting and restoring torques acting on the coil of a moving coil galvanometer satisfy the condition:
The poles of the permanent magnet used in a moving coil galvanometer are shaped as:
In a suspended-coil galvanometer, the phosphor-bronze strip serves to:
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:
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:
