A chest x-ray uses 10 keV photons. A 60 kg person receives a 30 mrem dose from one x-ray that exposes 25% of the patient’s body. How many x-ray photons are absorbed in the patient’s body?
What is the activity in and in of a 2.0 mg sample of ?
The first three energy levels of the fictitious element X are shown in Figure P29.56. Hint: The energy of the photon is not the energy transferred to the atom in the collision. Part A What wavelengths are observed in the absorption spectrum of element X? Give your answers in nm. Part B State whether each of your FIGURE P29.56 wavelengths in […]
If the nucleus is a few fm in diameter, the distance between the centers of two protons must be = 2 fm. Part A Calculate the repulsive electric force between two protons that are 2.0 fm apart. Part B Calculate the attractive gravitational force between two protons that are 2.0 fm apart. Could gravity be the force […]
The material that formed the earth was created in a supernova explosion approximately 6 billion years ago. The two most common isotopes of uranium, 238U and 235U were created in roughly equal amounts. Today, the earth contains more than 100 times as much 238U as 235U. Part A Which isotope has a longer half-life? Select […]
Radioactive isotopes are often used for medical imaging. Technetium-99m (99mTc) is a particularly popular isotope since it has a short half-life and is easy to make. (The “m” in technetium-99m just means that the nucleus is in a metastable, i.e., excited, state.) Also, 99mTc can be chemically bonded to a number of different compounds and […]
The technetium isotope 99Tc is useful in medical imaging, but its short 6.0 h half-life means that shipping it from a source won’t work; it must be created where it will be used. Hospitals extract the 99Tc daughter product from the decay of the molybdenum isotope 99Mo. The 99Mo source has a half-life of 2.7 […]
Many medical PET scans use the isotope 18F, which has a half-life of 1.8 h . A sample prepared at 10:00 a.m. has an activity of 28 mCi . Part A What is the activity at 1:00 p.m., when the patient is injected? Express your answer using two significant figures.
The radioactive isotope 133 54Xe is used in pulmonary respiratory studies to image the blood flow and the air reaching the lungs. The half-life of this isotope is 5 days. Part A A hospital needs 0.100 g of 133 54Xe for a lung-imaging test. If it takes 10 days to receive the shipment, what is […]
Measurements of the radioactivity of a certain isotope tell you that the decay rate decreases from 8280 decays per minute to 3160 decays per minute over a period of 5.00 days . Part A What is the half-life T1/2 of this isotope? Express your answer numerically, in days, to three significant figures.