Many radioisotopes have important industrial, medical, and research applications. one of these is 60co, which has a half-life of 5.20 years and decays by the emission of a beta particle (energy 0.310 mev) and two gamma photons (energies 1.17 mev and 1.33 mev). a scientist wishes to prepare a 60co sealed source that will have an activity of at least 13.7 ci after 24.0 months of use. if the activity is 16.0 ci, how many 60co atoms are in the source?

If you were designing a bumper for a car, would you prefer it to exhibit elastic or plastic deformation? why? consider the functions of a bumper in both a minor "fender-bender" and a major collision.

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?