An object of mass $2kg$ is whirled round in a vertical circle of radius $1m$ with a constant speed of $4m{s}^{-1}.$ The maximum tension in the string is $(g=10m{s}^{-2})$  

For the maximum tension in the string, the object should be at the lowest position of the  vertical circle, Then $T=mg+\frac{m{v}^2}{r}=2\times 10+\frac{(2\times 16)}{1}=52N$  
So, the correct answer is 2