The given information is insufficient to find the amount of energy absorbed. In principle, you could figure it out if you knew either (a) how much energy is in the radiation and what fraction of it was absorbed by the body, or (b) the rate at which the body's temperature changes in response to a given transfer of heat (i.e., the specific heat.)
If there's no way of finding the specific heat, you would need to know the absorptivity of the body and the temperature of the incident radiation (assuming that it's well-approximated by a blackbody.) You would also need to assume that the radiation is hitting all sides of the object evenly and not just from one side (say.)