If two persons A and B take 2 s and 4 s respectively to lift an object to the same height h, then the ratio of their powers is [Kerala CEE 2014)

Given,   t1=2 s,t2=4 s and h1=h2=hAs,    PA=mgh1t1                     …(i)and    PB=mgh2t2                    …(ii)On dividing Eq. (i) by Eq. (ii), we getPA:PB=mgh1/t1mgh2/t2=h1h2t2t1=t2t1=42=21  ∵h1=h2⇒PA:PB=2:1