Question

A galvanometer can be converted into a voltmeter by connecting:
A. Low resistance in parallel
B. Low resistance in series
C. High resistance in parallel
D. High resistance in series

Answer 1

Hint: In order to solve this problem we need to know that voltmeter needs high resistance to measure the potential difference more accurately. Knowing this will solve your problem and will give you the right answer.

Complete step-by-step answer:
Galvanometer:
Galvanometer is an instrument for measuring a small electrical current or a current feature by deflection of a moving coil. Deflection is a mechanical motion arising from the force of the current. Galvanometer operates on the concept of transforming electrical energy into mechanical energy. As a current flows through a magnetic field, a magnetic torque is felt. If it is free to rotate under a guiding force, it rotates by an angle equal to the current flowing through it.

Voltmeter:
A voltmeter is an instrument used to measure the electrical potential difference between two points in an electrical circuit. Analog voltmeters shift the pointer over a scale in relation to the voltage of the circuit; digital voltmeters show the voltage by means of an analog – to – digital converter. The fundamental theory of the voltmeter is that it must be wired parallel to the voltage that we want to calculate. The parallel connection is used as the voltmeter is built in such a way that it has a very high resistance value.

In order to convert a galvanometer to a voltmeter, a high resistance is connected to it in series. Since voltmeter can measure the potential voltage more accurately only with the help of high resistance.

So, the correct option is D, high resistance in series.

Note – When you need to solve problems on voltmeter then you have to consider high resistance in series so that it shows the potential difference more and more accurately. When it is said about ammeters then you have to consider the low resistance in parallel so that the total