actualli the meissner effect does not depend on lenz's law..its one explanation that makes perfect sense..but isnt always tru..coz we did the meissner prac by coolin ybco then placin the magnet over it (like u sed iz the eddy currents)..but we also did the whole thing again and had the magnet on the ybco before we cooled..and when we did cool it below tc the magnet levitated...magic!..they call it diamagnetism apparently...couldnt hav been lenzs law in this case coz there was no initial relative motion......what does it matter tho?..phyz iz ova!!