Voltmeter MCQ - Practice Questions with Answers

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

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

The actual value of resistance $R$, shown in the figure is $30 \Omega$. This is measured in an experiment as shown using the standard formula $R=\frac{V}{I}$, Where } V and } I are the readings of the voltmeter and ammeter, respectively. If the measured value of R is $5 \%$ less, then the internal resistance (in $\Omega$ ) of the voltmeter is: (Round the answer to the nearest integer)

An ideal voltmeter V is connected to a $20 \Omega$ resistor and a battery with emf 10V and internal resistance $0.5 \Omega$ as in the figure.

The ratio of current in $20 \Omega$ resistor with the voltage of the battery

In the given circuit, the voltmeter and the electric cell are ideal. Find the reading of the voltmeter

A constant 60 V d.c. supply is connected across two resistors of resistance $400 \mathrm{k} \Omega$ and $200 \mathrm{k} \Omega$. What is the reading of the voltmeter, also of resistance $200 \mathrm{k} \Omega$, when connected across the second resistor as shown in Figure?

An ammeter A of finite resistance and a resistor R are joined in series to an ideal cell C. A Potentiometer P is joined in parallel to R. The ammeter reading is $\mathrm{I}_0$ and the potentiometer reading is $\mathrm{V}_0$. P is now replaced by a voltmeter of finite resistance. The ammeter reading now is I and the voltmeter reading is V. Then

A constant voltage dc source is connected, as shown in Figure, across two resistors of resistances $400 \mathrm{k} \Omega$ and $100 \mathrm{k} \Omega$

What is the reading of the voltmeter, also of resistance $100 \mathrm{k} \Omega$, when connected across the second resistor as shown?

A, B and C are voltmeters of resistance R, 1.5 R and 3 R, respectively. When some potential difference is applied between X and Y, the voltmeter reading are and , respectively. Then

A voltmeter having a resistance of $1800 \Omega$ is employed to measure the potential difference across $200 \Omega$ resistance which is connected to be power supply of 50 V and internal resistance $20 \Omega$. What is the approximate percentage change in the p.d. across $200 \Omega$ resistance as a result of connecting the voltmeter across it?