Q. No.In a moving coil galvanometer, two moving coils \(𝑀_1\) and \(𝑀_2\) have the following particulars:
\( R_1=5~ \Omega, N_1=15, A_1=3.6 \times 10^{-3} ~\text{m}^2, B_1=0.25 ~\text{T} \)
\(R_2=7 ~\Omega, N_2=21, A_2=1.8 \times 10^{-3} ~\text{m}^2, B_2=0.50 ~\text{T} \)
Assuming that torsional constant of the springs are same for both coils, what will be the ratio of voltage sensitivity of \(M_1\) and \(M_2\)?
1. \(1:3\)
2. \(1:2\)
3. \(1:4\)
4. \(1:1\)
\( R_1=5~ \Omega, N_1=15, A_1=3.6 \times 10^{-3} ~\text{m}^2, B_1=0.25 ~\text{T} \)
\(R_2=7 ~\Omega, N_2=21, A_2=1.8 \times 10^{-3} ~\text{m}^2, B_2=0.50 ~\text{T} \)
Assuming that torsional constant of the springs are same for both coils, what will be the ratio of voltage sensitivity of \(M_1\) and \(M_2\)?
1. \(1:3\)
2. \(1:2\)
3. \(1:4\)
4. \(1:1\)
Subtopic: Moving Coil Galvanometer |
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A galvanometer having a coil of resistance \(30~\Omega\) need \(20~\text{mA}\) of current for full-scale deflection. A maximum current of \(3~\text A\) is to be measured using this galvanometer. The resistance of the shunt to be added to the galvanometer should be \(\dfrac{30}{X}~\Omega,\), where \(X\) is.
1. \(149\)
2. \(298\)
3. \(596\)
4. \(447\)
1. \(149\)
2. \(298\)
3. \(596\)
4. \(447\)
Subtopic: Moving Coil Galvanometer |
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Consider a moving coil galvanometer (MCG):
Choose the correct answer from the options given below:
1. B, D, E only
2. A, D only
3. A, B only
4. A, B, E only
| A. | The torsional constant in moving coil galvanometer has dimensions \([ML^2 T^{-2}]\) |
| B. | Increasing the current sensitivity may not necessarily increase the voltage sensitivity. |
| C. | If we increase number of turns \(N\) to its double \(2N,\) then the voltage sensitivity doubles. |
| D. | MCG can be converted into an ammeter by introducing a shunt resistance of large value in parallel with galvanometer. |
| E. | Current sensitivity of MCG depends inversely on number of turns of coil. |
1. B, D, E only
2. A, D only
3. A, B only
4. A, B, E only
Subtopic: Moving Coil Galvanometer |
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A galvanometer has a coil of resistance \(200~ \Omega\) with a full scale deflection at \(20 \mu \mathrm{~A}\). The value of resistance to be added to use it as an ammeter of range \((0-20)~\text{mA}\) is:
1. \(0.50 \Omega\)
2. \(0.40 \Omega\)
3. \(0.20 \Omega\)
4. \(0.10 \Omega\)
1. \(0.50 \Omega\)
2. \(0.40 \Omega\)
3. \(0.20 \Omega\)
4. \(0.10 \Omega\)
Subtopic: Moving Coil Galvanometer |
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Resistance of a galvanometer is \({G}.\) When it is converted into an ammeter, \(5\%\) of total current passes through the galvanometer's coil then the resistance of the shunt is:
1. \(\dfrac{G}{10}=S\)
2. \(\dfrac{G}{15}=S\)
3. \(\dfrac{G}{20}=S\)
4. \(\dfrac{G}{19}=S\)
1. \(\dfrac{G}{10}=S\)
2. \(\dfrac{G}{15}=S\)
3. \(\dfrac{G}{20}=S\)
4. \(\dfrac{G}{19}=S\)
Subtopic: Moving Coil Galvanometer |
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In a moving coil galvanometer, the coil experiences a deflection of \(0.05~\text{rad}\) when a current of \(10~\text{mA}\) flows through it. The torsional constant of the suspension wire is \(4\times10^{-5}~\text{N-m/rad},\) and the magnetic field is \(0.01~\text{T}.\) If the coil has \(200\) turns, what is the area of each turn (in \(\text{cm}^2\))?
1. \(1\)
2. \(2\)
3. \(3\)
4. \(4\)
1. \(1\)
2. \(2\)
3. \(3\)
4. \(4\)
Subtopic: Moving Coil Galvanometer |
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If the current \(200~\mu\text{A}\) deflects the coil of the moving coil galvanometer through \(60^\circ,\) then the current required to cause deflection through \(\pi\over 10\) radians is:
1. \(60~\mu\text{A}\)
2. \(50~\mu\text{A}\)
3. \(20~\mu\text{A}\)
4. \(150~\mu\text{A}\)
1. \(60~\mu\text{A}\)
2. \(50~\mu\text{A}\)
3. \(20~\mu\text{A}\)
4. \(150~\mu\text{A}\)
Subtopic: Moving Coil Galvanometer |
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Consider the circuit shown. The galvanometer has a resistance of \(10~\Omega\) and a current of \(3~\text{mA}\) flows through it. What is the resistance of the shunt?
| 1. | \(10^{-3}~\Omega\) | 2. | \(7.5\times10^{-3}~\Omega\) |
| 3. | \(6.75\times10^{-3}~\Omega\) | 4. | \(3.75\times10^{-3}~\Omega\) |
Subtopic: Moving Coil Galvanometer |
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In a moving coil galvanometer, if the number of turns in the coil increase by \(25 \text{%},\) the change in voltage sensitivity is:
1. zero
2. \(1 \text{%}\)
3. \(25 \text{%}\)
4. \(50 \text{%}\)
1. zero
2. \(1 \text{%}\)
3. \(25 \text{%}\)
4. \(50 \text{%}\)
Subtopic: Moving Coil Galvanometer |
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In a moving coil galvanometer, the number of turns in the coil are increased to increase the current sensitivity by \(50\text{%}.\) The percentage change in voltage sensitivity is:
1. \(-50\text{%}\)
2. \(50\text{%}\)
3. no change
4. \(25\text{%}\)
1. \(-50\text{%}\)
2. \(50\text{%}\)
3. no change
4. \(25\text{%}\)
Subtopic: Moving Coil Galvanometer |
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