would this hard drive be enough for 1TB iMac

i have an iMac21.5/7QC\2X2GB/1TB/6770M bought last year.
Would Western Digital's My passport for MAC portable storage of 500 GB Go
be enough for my back up

WD 500GB My Passport Air for Mac USB 3.0 Portable Hard Drive

WD 500GB My Passport Air for Mac USB 3.0 Portable Hard Drive

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