To convert the given galvanometer of known resistance and figure of merit into a voltmeter of a desired range and verify the same. Galvanometer is a sense that a device used to detect very low current. Its working is based on the principle that a coil placed in a uniform magnetic field experiences a torque when an electric current is set up in it. Madam, how can we convert the given galvanometer of known resistance and figure of merit into a voltmeter of a desired range and verify the same? A galvanometer can be converted into a voltmeter of desired range by connecting a suitable high resistance R in its series. Let G be the resistance of the galvanometer which gives full-scale deflection when I G current flows through it. Let V is the range of the voltmeter in which the galvanometer has to be converted and R is the resistance required to connect in series with the galvanometer. Then resistance R is given by R is equal to V by I G minus G. Let's do an experiment to convert the given galvanometer of known resistance and figure of merit into a voltmeter of a desired range and verify the same. Our aim here is to convert the given galvanometer of known resistance and figure of merit into a voltmeter of a desired range and verify the same. A parameters required are a Western type galvanometer of known resistance and figure of merit, a battery, a real start, one-way key, a resistance box of the range 0 to 10,000 ohm, a voltmeter of 0 to 3 volt range connecting wires and sandpaper. Procedure A conversion of the galvanometer into voltmeter, no term the given value of galvanometer resistance G and its figure of merit, K. Note the total number of divisions N on either side of the zero of the galvanometer. Calculate the value of current I G with the help of the relation I G is equal to N K for which galvanometer shows full-scale deflection. Calculate the value of required series resistance R to be connected in series with the galvanometer for the conversion of the given galvanometer into voltmeter of given range by the relation R is equal to V by I G minus G. Connector resistance box of range 0 to 10,000 ohm in series with the given galvanometer and take out the plugs of resistance R from it. Now the given galvanometer with this resistance in series is converted into voltmeter of the given range V volt. B, verification of the converted voltmeter, draw a neat circuit diagram for the verification of the converted voltmeter. Remove insulation from the ends of the connecting wire using a sandpaper. Arrange the apparatus according to the circuit diagram and make all connections neat and tight. Take out the plugs of calculated resistance R from the resistance box of the range 0 to 10,000 ohm and insert the key K and adjust the real start to obtain maximum deflection in the galvanometer. Note the readings of standard voltmeter and galvanometer. Can word the galvanometer reading into volt and find the difference between them. If any, this difference gives the error. Take four more observations by changing the resistance with the help of the real start over the whole range of the voltmeter. Record all the observations in a tabular form. Observation given resistance of the galvanometer G is equal to X ohm. Given value of the figure of merit of the galvanometer K is equal to A by division. Total number of divisions on either side of the zero of the galvanometer N is equal to X divisions. Current for full scale deflection I G is equal to N K is equal to X ampere. Range of conversion of the converted voltmeter V is equal to X ohm. Value of the required series resistance R is equal to V by I G minus G is equal to X ohm. Least count of the converted voltmeter V by N is equal to X volt. Least count of the standard voltmeter is equal to X volt. Table for the verification of converted voltmeter. Zero number. Reading of converted voltmeter. Deflection theta division. Potential difference 3 1 is equal to theta into LC. Volt. Standard voltmeter reading V2 volt. Difference error V2 minus V1. Volt. Result. The value of the required series resistance to be connected in series with the galvanometer to convert it into voltmeter of the given range is equal to X ohm. Value of the current for full scale deflection I G is equal to X ampere. The difference between the values of standard voltmeter and converted voltmeter that is V2 minus V1 is very small. Hence, conversion of the given galvanometer into voltmeter of the given range is perfect. Precautions. All the connections should be neat clean and tight. The resistance box to be used in series should have a very high resistance as compared to resistance of galvanometer and that to be used in parallel should have a low resistance. A freshly charged battery should be used so that its EMF may remain constant throughout the experiment. All plugs in the resistance box should be tight. The deflection in galvanometer should be large. The real start should be used as a potential divider. The voltmeter used for verification should preferably be of the same order as the range of conversion. Sources of error the EMF of the battery may change during the experiment. Calibration of resistance in resistance box may not be correct. Plugs in resistance box may not be tight and may have contact resistance. The galvanometer divisions may not be of equal size. Thank you, ma'am, for this knowledgeable experiment.