WELL I THINK ITS B'COZ(i m not sure )

RATE OF CHANGE OF MAGNETIC FLUX IS MORE THIS TIME(2nd time) 

AS THERE IS AN CURRENT IN THE 2nd CIRCUIT ALSO

WHICH GENERATES  THE MAGNETIC FIELD OF ITS OWN

SO AS THE CIRCUIT IS OPEN the magnetic flux changes in both circuit

hence deflection is more

(i feel i m correct , but not sure)

 in dis case, d magnetic flux linked wid d other circuit changes gradually....at first whn d key is closed an induced emf is produced in d 2nd circuit.....bt since d currect is const.( DC) after some time G will return to its original position.......but whn d key in d 1st circuit is opened again,,,,,magnetic flux changes again...but this time d flux changes from maximum to zero.....so more deflection is observed....

 plz tell me if u hv any confusion abt it.....

Check the graph for the current as a function of time for such a circuit.

You will find that the current takes more time to build up to its maximum value form zero tan it takes to die out.

So, although the flux change is same, time requirec in the second case is less and hence the rate of change of flux is more, resulting in greater deflection.

Rate me.

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