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.
Part A Use the data in Appendix D in the textbook to calculate the chemical atomic mass of neon, to two decimal places. Express your answer using two decimal places.
Consider the nuclear fusion reaction 2H+6Li→4He+4He. Part A Compute the binding energy of the 2H. Express your answer using three significant figures. Part B Compute the binding energy of the 6Li. Express your answer using three significant figures. Part C Compute the binding energy of the 4He. Express your answer using three significant figures. Part […]
In LASIK surgery, a laser is used to reshape the cornea of the eye to improve vision. The laser produces extremely short pulses of light, each containing 1.0 mJ of energy. Part A In each pulse there are 9.7×1014 photons. What is the wavelength of the laser? Express your answer with the appropriate units. Part […]
Hydrogen gas absorbs light of wavelength 103 nm. Part A Afterward, what wavelengths are seen in the emission spectrum? Enter your answers in descending order separated by commas.