A cobalt-60 source with activity 2.60×10-4 Ci is embedded in a tumor that has mass 0.20 kg. The source emits gamma photons with average energy 1.25 MeV. half the photons are absorbed in the tumor, and half escape. i. What energy is delivered to the tumor per second? ii. What absorbed dose, in rad, is delivered per second? iii. What equivalent dose, in rem, is delivered per second if the RBE for these gamma rays is 0.70? iv. What exposure time is required for an equivalent dose of 200 rem? B. A laser with power output of 2.0 mW at a wavelength of 400 nm is projected onto a Calcium metal. The binding energy is 2.31 eV. i. How many electrons per second are ejected? ii. What power is carried away by the electrons? C. A hypodermic needle of diameter 1.19 mm and length 50 mm is used to withdraw blood from a patient? How long would it take for 500 ml of blood to be taken? Assume a blood viscosity of 0.0027 Pa.s and a pressure in the vein of 1,900 Pa. D. A person with lymphoma receives a dose of 35 gray in the form of gamma radiation during a course of radiotherapy. Most of this dose is absorbed in 18 grams of cancerous lymphatic tissue. i. How much energy is absorbed by the cancerous tissue? ii. If this treatment consists of five 15-minute sessions per week over the course of 5 weeks and just one percent of the gamma photons in the gamma ray beam are absorbed, what is the power of the gamma ray beam? iii. If the gamma ray beam consists of just 0.5 percent of the photons emitted by the gamma source, each of which has an energy of 0.03 MeV, what is the activity, in Curies, of the gamma ray source? E. A water heater that is connected across the terminals of a 15.0 V power supply is able to heat 250 ml of water from room temperature of 25°C to boiling point in 45.0 secs. What is the resistance of the heater? The density of water is 1,000 kg/m2 and the specific heat capacity of water is 4,200 J/kg/°C.
Radioactive decay
The emission of energy to produce ionizing radiation is known as radioactive decay. Alpha, beta particles, and gamma rays are examples of ionizing radiation that could be released. Radioactive decay happens in radionuclides, which are imbalanced atoms. This periodic table's elements come in a variety of shapes and sizes. Several of these kinds are stable like nitrogen-14, hydrogen-2, and potassium-40, whereas others are not like uranium-238. In nature, one of the most stable phases of an element is usually the most prevalent. Every element, meanwhile, has an unstable state. Unstable variants are radioactive and release ionizing radiation. Certain elements, including uranium, have no stable forms and are constantly radioactive. Radionuclides are elements that release ionizing radiation.
Artificial Radioactivity
The radioactivity can be simply referred to as particle emission from nuclei due to the nuclear instability. There are different types of radiation such as alpha, beta and gamma radiation. Along with these there are different types of decay as well.
A cobalt-60 source with activity 2.60×10-4 Ci is embedded in a tumor that has mass 0.20 kg. The source emits gamma photons with average energy 1.25 MeV. half the photons are absorbed in the tumor, and half escape. i. What energy is delivered to the tumor per second? ii. What absorbed dose, in rad, is delivered per second? iii. What equivalent dose, in rem, is delivered per second if the RBE for these gamma rays is 0.70? iv. What exposure time is required for an equivalent dose of 200 rem? B. A laser with power output of 2.0 mW at a wavelength of 400 nm is projected onto a Calcium metal. The binding energy is 2.31 eV. i. How many electrons per second are ejected? ii. What power is carried away by the electrons? C. A hypodermic needle of diameter 1.19 mm and length 50 mm is used to withdraw blood from a patient? How long would it take for 500 ml of blood to be taken? Assume a blood viscosity of 0.0027 Pa.s and a pressure in the vein of 1,900 Pa. D. A person with lymphoma receives a dose of 35 gray in the form of gamma
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