Rankine's Formula

Q. Assertion (A): Rankine's theory is generally used for finding out the buckling load of intermediate columns.
Reason (R): Euler's theory gives higher values for buckling loads in intermediate columns.

1. both A and R are true and R is the correct explanation of A
2. both A and R are true but R is not a correct explanation of A
3. A is true but R is false
4. A is false but R is true

Q. If the Euler load for a steel column is $1000kN$ and crushing load is $1500kN$, the Rankine load is equal to

1. $2500kN$
2. $1500kN$
3. $1000kN$
4. $600kN$