Atomic and Nuclear Physics Answers

50V has one of the longest known radioactive half-lives. In a difficult experiment, a researcher found that the activity of 1.00 kg of 50V is 1.75 Bq. What is the half-life in years?

Radioactive isotopes used in cancer therapy have a "shelf- life," like pharmaceuticals used in chemotherapy. Just after it has been manufactured in a nuclear reactor, the activity of a sample of 60co is 5000 Ci. When its activity falls below 3500 Ci, it is considered too weak a source to use in treatment. You work in the radiology department of a large hospital. One of these 60co sources in your inventory was manufactured on October 6, 2004. It is now April 6, 2007. Is the source still usable? The half-life of 60co is 5.271 years.
a) What is the mass of the source when it was manufactured?
b) Is this source still useable?

a fan blade is initially rotating at an angular speed of 48.6 rpm. it slows down and eventually comes to rest in a time of 32 seconds after turning through a total of 8.8 revolutions. find the average angular velocity of the fan blade

what is the maximuim energy resolution necessary to resolve two peaks at 720 KeV and 755 KeV?

what is the reaction force of centripetal force?

WHY ARE THE BRIDGE DECLARED UNSAFE AFTER A LONG USE?

Hi
Theres a few questions i need to checkmy work on. the questions are
1.What is the frequency of a photon with a wavelength of 1040 nm. Report your answers to three significant digits.
The frequency is = _________ s-1

2.What is the energy of a photon with a wavelength of 260 nm. Report your answers to three significant digits.

3.In the Bohr model of the hydrogen atom, the n=1 to n=4 electronic transition corresponds with an ______ of energy; the change in the energy of the atom in this process is a _______ value.

why the spin of electron is half ?