UPS backup time

[gags]

I would like to know how much backuptime will a single battery UPS can give if I have to connect only a modem to it.

And, On what factors do this backuptime depends?

Thanks

[the.kaushik]

backup time depends on the amount of current intake(Inversely proportional to amount of current intake in watts). I have a apc ups and when there is load shedding i use my bsnl wireless modem to browse.. my laptop gives 3.2 hrs backup till then i works as above that i haven't check.. should work for some 6 -7 hrs i think