$$R=1Omega$$ $$X_L=omega L=(2pi f)L=pi Omega$$ Phase difference - $$cosphi=dfrac{R}{Z}=dfrac{R}{sqrt{R^2+X_L^2}}$$ and the current lags the emf as this is an inductive circuit $$implies cosphi=dfrac{R}{Z}=dfrac{1}{sqrt{1+pi^2}}=0.303$$ $$implies phi=72.34^o$$