Voltmeter

Q. In the circuits shown below, the readings of the voltmeter and the ammeter will be

1. $V_2>V_1$ and $i_1=i_2$
2. $V_2>V_1$ and $i_1>i_2$
3. $V_1=V_2$ and $i_1>i_2$
4. $V_1=V_2$ and $i_1=i_2$

Q.

Power loss during transmission is calculated using the formula P=I²R but not using the formula P=VI.why?

Q.

Why voltmeter is connected in parallel?

Q.

A galvanometer coil has a resistance of 15 ohm and the metre shows full scale deflection for a current of 4mA. How will you convert the metre into an ammeter of range 0 to 6 A?

Q.

How do you increase the range of an ammeter?

Q. $A,B$ and $C$ are voltmeters of resistance $R,1.5R$ and $3R$ respectively. When some potential difference is applied between $X$ and $Y$, the voltmeter readings are $V_A,V_B$ and $V_C$ respectively. Then

1. $V_A=V_B=V_C$
2. $V_A\ne V_B=V_C$
3. $V_A=V_B\ne V_C$
4. $V_A\ne V_B=V_C$

Q. $20\%$ of the main current passes through the galvanometer. If the resistance of the galvanometer is $G$, then the resistance of the shunt will be -

1. $\frac{G}{50}$
2. $\frac{G}{4}$
3. $50G$
4. $9G$

Q. The resistance of a galvanometer is $10\Omega$. It gives full-scale deflection when $1mA$ current is passed. The resistance connected in series for converting it into a voltmeter of $2.5V$ will be

1. $24.9\Omega$
2. $249\Omega$
3. $24900\Omega$
4. $2490\Omega$

Q. The scale of galvanometer is divided into 150 equal divisions. The galvanometer has a current sensitivity of 10 divisions per $mA$ and the voltage sensitivity of 2 divisions per $mV$. How can the galvanometer be designed to read:

I. 6 A per division
The value of shunt is $\times {10}^{-5}\Omega$

II. 1 V per division
The value of resistance to be connected in series is $\Omega$

Q. A galvanometer has a resistance of $50\Omega$ and its full-scale deflection current is $50\mu \text{A}$. What shunt resistance should be added so that the ammeter can have a range of $0-5\text{mA}$ ?

1. $0.2\Omega$
2. $0.5\Omega$
3. $1.2\Omega$
4. $1.5\Omega$

Q. A moving coil galvanometer has $50$ turns and each turn has an area $2\times {10}^{-4}{m}^2$. The magnetic field produced by the magnet inside the galvanometer is $0.02T$. The torsional constant of the suspension wire is ${10}^{-4}Nm-ra{d}^{-1}$. When a current flows through the galvanometer, a full-scale deflection occurs if the coil rotates by $0.2rad$. The resistance of the coil of the galvanometer is $50\Omega$. This galvanometer is to be converted into an ammeter capable of measuring current in the range $0-1.0A$. For this purpose, a shunt resistance is to be added in parallel to the galvanometer. The value of this shunt resistance, in ohms, is

Q. In the given circuit the internal resistance of the $18\text{V}$ cell is negligible. If $R_1=400\Omega ,R_3=100\Omega$ and $R_4=500\Omega$ and the reading on an ideal voltmeter across $R_4$ is $5\text{V}$, then the value of $R_2$ will be

1. $230\Omega$
2. $300\Omega$
3. $450\Omega$
4. $550\Omega$

Q. A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10 divisions per milliampere and voltage sensitivity is 2 divisionsper millivolt. In order that each division reads 1volt, the resistance in ohms needed to be connectedin series with the coil will be:(a) 9995(c) 105(b) 99995(d) 103

Q. 10. A Voltmeter is connected in parallel with a variable resistance R which is in series with an ammeter and a cell as shown in the figure. For one value of R, the meter reads 0.3A and 0.9V . For another value of R the reading are 0.25 A and 1.0 V. What is the internal resistance of

Q.

Why are measured voltages smaller than theoretical?

Q.

A galvanometer with resistance $100\mathrm{\Omega }$ gives full scale deflection with a current of $10\mathrm{mA}$. The value of shunt, in order to convert it into an ammeter of $10$ ampere range, will be ___________.

Q. A galvanometer, whose resistance is $50\text{ohm}$, has $25$ divisions in it. When a current of $4\times {10}^{-4}\text{A}$ passes through it, its needle (pointer) deflects by one division. To use this galvanometer as a voltmeter of range $2.5\text{V}$, it should be connected to a resistance of :

1. $\text{6250 ohm}$
2. $\text{250 ohm}$
3. $\text{6200 ohm}$
4. $\text{200 ohm}$

Q. A micro meter has a resistance of $100\Omega$ and a full scale of range of $50\mu \text{A}$. It can be used as a voltmeter or a higher range ammeter provided a resistance is added to it. Pick the correct range and resistance combinations(s).

1. $50\text{V}$ range with $10\text{k}\Omega$ resistance in series
2. $10\text{V}$ range with $200\text{k}\Omega$ resistance in series
3. $5\text{mA}$ range with $1\Omega$ resistance in parallel
4. $10\text{mA}$ range with $1\text{k}\Omega$ resistance in parallel

Q. The resistance of a galvanometer is $50\Omega$ and the maximum current which can be passed through it is $0.002\text{A}.$ What resistance must be connected to it in order to convert it into an ammeter of range $0-0.5\text{A}$?

1. $0.002\Omega$
2. $0.02\Omega$
3. $0.2\Omega$
4. $0.5\Omega$

Q. a galvanometer of resis†an ce 2 ohm is to be converted into an ammeter so tjat its range is increased by 100 times of its initial range. the value of shunt resis†an ce required is ?

Q.

Name the device used to measure electric current and potential in the circuit. How are they connected?

Q. The meter bridge is based on the principle of

1. balanced Wheatstone bridge
2. kirchoff’s bridge
3. fran de meter’s bridge
4. fraun de volte’s bridge

Q. the resistance of moving coil galvanometer is 195ohm and its FSD current is 100mA .the resistance required to be connected to convert it into ammeter of range 4A is

Q. A galvanometer of resistance $100\Omega$ has $50$ divisions on its scale and has sensitivity of $20\mu \text{A}/\text{division}.$ It is to be converted to a voltmeter with three ranges, of $0-2\text{V},0-10\text{V}$ and $0-20\text{V}$ The appropriate circuit to do is

1. 
2. 
3. 
4. 

Q. An ammeter is designed by shunting $12\Omega$ galvanometer with $6\Omega$ resistance, the additional shunt that should be connected across it to quadruple the range is

1. $4\Omega$
2. $3\Omega$
3. $\frac{4}{3}\Omega$
4. $\frac{3}{4}\Omega$

Q. The scale of a galvanometer of resistance $100\Omega$ contains 25 divisions. It gives a deflection of one division on passing a current of $4\times {10}^{-4}A$. The resistance in ohms to be added to it, so that it may become a voltmeter of range 2.5 volt is

1. 100
2. 150
3. 300
4. 250

Q. For the circuit shown in figure, the equivalent resistance between $\text{A}$ and $\text{C}$ will be

1. $\frac{12r}{11}$
2. $\frac{13r}{11}$
3. $\frac{14r}{11}$​​​​
4. $\frac{15r}{11}$​​

Q. You are given a $2\mu F$ parallel plate capacitor. How would you establish an instantaneous displacement current of
1 mA in the space between its plates?

Q.

Which instrument is used to measure electric current? How should it be connected in a circuit?

Q. A galvanometer of coil resistance $99\Omega$ is converted into an ammeter using shunt of $1\Omega$ and is connected as shown in Figure - 1. Ammeter reads 3A. If same galvanometer is converted into voltmeter by connecting a $101\Omega$ resistance in series this voltmeter reads $\frac{4}{5}$ of full scale reading as shown in Figure - 2

1. Internal resistance of cell is $r=1.01\Omega$
2. Range of ammeter is 5A
3. Range of voltmeter is 10V
4. Full scale deflection current of galvanometer is 0.05A