When I magnetize water by circular magnets of strength 0.8 T, how long will the magnetism be present in the water? I mean, how many days will it be in the water?


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  • $\begingroup$ Hi venkatesh, welcome to Physics SE. Please note that you have to show your own effort in answering your question, and point out to us, where your actual problem is. $\endgroup$ – flaudemus Feb 28 at 18:40

The quantity you're asking for is called the "relaxation time" and is useful when performing NMR. There are many tables for this sort of thing, but just going off of Wikipedia, the atomic nuclei for water should lose their magnetization in about 1 second. The electrons, which are much more exposed, lose their magnetization even faster than that.

  • $\begingroup$ The medical literature on MRI has loads of data on T1 relaxation times in various tissues and tumors. $\endgroup$ – Bert Barrois Feb 28 at 14:14

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