i am demonstrating meterbridge experiment Aim of this experiment apparatus required for this expeiment Now i connected unknown resistance in left gap If the balancing length from left is L X=R*L/(100-L) we can analyse connections from point A, connect wire to the positive terminal of battery from negative terminal connect wire to key from key, using a lengthy wire connect to point B now switch on battery now voltage level is opted as 2 V now balancing length is measured from left side we can check whether the connections are correct when we touch left side A if the deflection is towards left, then , when we touch right side B the deflection should be towards right or vice versa… (deflection should be opposite). now method of taking readings since unknown resister is connected at left gap,balancing length should measured from left move jockey from left until galvanometer deflection is zero at this point of contact deflection is zero so length from left is measured as 46 cm from the scale note reading in column next set R=3 ohm key to select 3 ohm is not available therefore open both keys ( 2 + 1=3 ohm) similarly by setting R=4 , R=5 and R=6 repeat the experiments to find balancing length correspondingly now to find right side balancing length interchange left gap and right gap connection ( unknown wire and resistance box ) set R=1 ohm and measure balancing length from right side use reading in the bottom of scale move jockey from right side first reading 51 cm note down in second column for L2 similarly by setting R=2 , R=3 , R=4 …. etc repeat the experiments to find balancing length correspondingly now calculate mean length next column is 100-mean length Next column is to find X now calculate X by compleating full experiments and observation as given then finaly find mean value of X next to find resistivity use equation r=radius of given nichrome wire X=result from experiment find diameter using screw gauge just showing results only… if any doubt check screw guage video in this channl results