A $60$Co source with activity $14\mathrm{.}2$ Ci is embedded in a tumor that has a mass of $0\mathrm{.}505$ kg$.$ The Co source emits gamma$-$ray photons with average energy of $1\mathrm{.}25$ MeV. Half the photons are absorbed in the tumor, and half escape.

What energy is delivered to the tumor per second?

Express your answer in jouls per second.

What absorbed dose $($in rad$)$ is delivered per second?

Express your answer in rads.

What equivalent dose $($in rem$)$ is delivered per second if the RBE for these gamma rays is $0\mathrm{.}700?$

Express your answer in rem.

What exposure time is required for an equivalent dose of $200$ rem $?$

Express your answer with the appropriate units.