Two identical capacitors A and B are charged to the same potential and then made to discharge through resistances R_A and R_B respectively, with R_A > R_B.

time constant, 

${\tau }_{\mathrm{A}}={\mathrm{CR}}_{\mathrm{A}}\text{ ; }{\tau }_{\mathrm{B}}={\mathrm{CR}}_{\mathrm{B}}$

$\text{∵ }{\mathrm{R}}_{\mathrm{A}}>{\mathrm{R}}_{\mathrm{B}}\text{ ∴ }{\tau }_{\mathrm{A}}>{\tau }_{\mathrm{B}}$

Hence, A will take more time to discharge. 

Since, both capacitors are identical and charged to same potential, they will have same energy stored. So, same amount of energy will be dissipated in the form of heat.