Light year is a unit of    

(1) Time

(2) Mass

(3) Distance

(4) Energy

Which of the following is not represented in correct unit  

(1) $\frac{\text{Stress}}{\text{Strain}}=N\text{}/\text{}{m}^2$

(2) Surface tension = $N\text{}/\text{}m$

(3) Energy $=kg\text{-}m\text{}/\text{}\sec$

(4) Pressure $=N\text{}/\text{}{m}^2$

The unit of power is 

(1) Joule

(2) Joule per second only

(3) Joule per second and watt both

(4) Only watt