Radioactivity Questions and Answers

The half life of Lead 214 is 1584 s a What is the decay constant for Lead 214 b A 100 0 kg sample of Lead 214 is allowed to decay for 4752 s How many kg Lead 214 remain after that time

An unknown substance weighs 31 35kg when it is first brought to the lab After a week in the lab a technician weighs it again and finds it weighs 13 71kg Assuming t substance is decaying exponentially calculate the decay factor from week to week Write your answer as a decimal rounded to the nearest hundredth

What is the product of the alpha decay of 234U 92 O 234 U 92 230Th 90 234Th 91 234 Np

barium isotope 131 Ba has a half life of 12 s A 270 g sample of 131 Ba is prepared Part B Part C What is the mass of 131 Ba after 100 days Express your answer to two significant figures and include the appr

Measurements of a certain isotope tell you that the decay rate decreases from 8271 decays minute to 3138 decays minute over a period of 4 00 days Part A What is the half life T1 2 of this isotope Express your answer numerically in days to three significant figures View Available Hint s VAE BEZ

The half life of sodium 24 is 15 hours Starting with a sample of 50 grams how many grams of sodium 24 will remain after 45 hours 0 6 7 07 0 073 07 6

An astronomer is trying to estimate the surface temperature of a star with a radius of 5 0 x 108 m by modeling it as an ideal blackbody The astronomer has measured the intensity of radiation due to the star at a distance of 2 5 x 10 3 m and found it to be equal to 0 055 W m Given this information what is the temperature of the surface of the star Express your answer in kelvins to two significant figures View Available Hint s

Population of a certain insect grows according to the law of uninhibited growth This means that the growth is modeled by the function A t Agekt where A is the number of insects Ao is the initial number of insects k is the growth rate and t time is measured in days 1 If the number of insects doubles in six days what is the growth rate that gives the number of insects Show your work You can leave the answer as a fraction 6 pts The growth rate is Fill in the blank 2 If the growth rate of this insect is 3 per day and the initial number of the insect is 5 find the time in days when the number of insects to 20 Show your work You can leave the answer as a fraction 6 pts days Fill in the blank

Use the data table below to answer the next 4 questions note the table will be reproduced for each question Star 1 Star 2 Star 3 Star 4 O a Star 1 Ob Star 2 Star 3 Spectral Class c M Which of the stars is a red supergiant star A M Mass solar masses 50 40 2 0 2

The rest energy of an object is equal to what? one-half its mass times the speed of light its mass times the speed of light squared O its mass times acceleration due to gravity one-half its mass times its velocity squared

Deep in the core of the Sun, 620 million metric tons of hydrogen nuclei are converted into 616 million metric tons of helium nuclei every second. What happens to the "missing mass" in the Sun's core? The "missing mass" is converted to heat during an exothermic chemical reaction that produces a new chemical species. The "missing mass" is transformed into energy in a fission reaction. The "missing mass" is transformed into energy in a fusion reaction. The "missing mass" is converted to heat during an endothermic chemical reaction that produces a new chemical species.

What number completes the missing part of this nuclear equation?: 24 Na → 20F + 42α 11 __ Enter answer below

Nuclear reactions that occur in the Sun release a tremendous amount of energy. Which statement best describes the force that is responsible for the release of this energy? A. It is long ranged and holds the universe in place. B. It is long ranged and it holds all the electrons in chemical bonds. C. It is short ranged and it holds protons and neutrons in the atom. D. It is short ranged and holds the Sun and stars in the sky.

The combination of two atomic nuclei into one,accompanied by a release of energy, is called: A. fusion B. chain reaction C. fission D. radioactive decay

The Strong Nuclear Force is responsible for... A. Keeping the electrons in orbit around the nucleus B. Keeping the protons away from each other C. Bonding the nuclei of two atoms to each other D. Holding together protons and neutrons

Uranium-235 decays into thorium-231 by emitting an alpha particle. This process releases energy. Where does the energy come from? Select one: O The total mass of thorium-231 and an alpha particle is slightly less than the mass of uranium-. 235. This mass difference becomes energy. O Thorium-231 plus an alpha particle has four more protons than uranium-235. This proton difference becomes energy. O The mass of uranium-235 is slightly less than the total mass of thorium-231 and an alpha particle. This mass difference becomes energy. O Uranium-235 has four more protons than thorium- 231 plus an alpha particle. This proton difference becomes energy.

In a hydrogen fusion reaction, two lighter hydrogen nuclei merge to form a heavier, more stable helium nucleus. The energy that is released in a hydrogen fusion reaction is Select one: O less than the energy released in chemical reactions of hydrogen. O equal to the change in the mass of hydrogen during the reaction. O the same as the energy released in the fission reaction of hydrogen. O much greater than the energy released in a hydrogen chemical reaction.

Which of the following can be used to describe nuclear fission? Check all that apply. energy is released as light used in nuclear reactors used in atomic bombs not very efficient

Which of the following would be considered the cons of using nuclear fission? Check all that apply. the waste products include radioactive elements produces air pollution from smoke stacks there is a chance for large disaster accidents it is used in nuclear weapon generation

What are control rods in a nuclear reactor? they control the intensity of the chain reaction they are used for emergency notification they serve to fuel the nuclear reaction they absorb energy from the reaction to transmit

What is the rest energy of a neutron? (c = 2.9979 x 109 m/s, mn= 1.6749 x 10-27) 8.18 x 10-14 J 1.5053 x 10-10 J 2.73 x 10-22 J 1.5032 x 10-10 J

Which of the following are considered the pros to using nuclear fusion? Check all that apply. it happens at "normal" temperatures it generates an abundant amount of energy it is generally about 80% efficient there is no dangerous waste

The half-life of Barium-139 is 4.96 x 103 seconds. A sample contains 3.21 x 10¹7 nuclei. What is the decay constant for this decay? 2.22 x 10-4 s-1 1.40 x 10-4 s-1 1.67 x 10-4 S-1 5.43 x 10-4 s-1

Which of the following are true regarding beta plus decay? (Select all that apply) emits an antineutrino emits a neutrino the nucleus emits a high-energy electron the nucleus emits a high-energy positron

The half-life of Silver-105 is 3.57 x 106 seconds. A sample contains 5.78 x 1017 nuclei. What is the decay constant for this decay? 1.54 x 10-7 s-1 1.94 x 10-7 s-1 1.37 x 10-7 s-1 1.73 x 10-7 s-1

The half-life of Argon is 6.5 x 10^3 seconds. A sample contains 4.2 x 10¹7 nuclei. What is the decay constant for this decay? 1.07 x 10-4 s-1 2.25 x 10-4 s-1 1.55 x 10-4 s-1 7.63 x 10-4 S-1

A sample of 1.5x1010 atoms that decay by alpha. emission has a half-life of 70 min. How many alpha particles are emitted between t = 50 min and t = 200 min? Express your answer using two significant figures.

Two radioactive substances A and B have decay constants 5X and X respectively. At t = 0 they have the same number of nuclei. The ratio of number of nuclei of A to those of B will be

A radio isotope 'X' with a half life 1.4 × 10⁹ years decays to 'Y' which is stable. A sample of the rock from a cave was found to contain 'X' and 'Y' in the ratio 1: 7. The age of the rock is 1.96 × 10 years 3.92 × 10 years 4.20 × 10 years 8.40 × 10 years

A definite amount of solid NH4HS is placed in a flask already containing ammonia gas at a certain temperature and 0.1 atm pressure. NH4HS decomposes to give NH3 and H₂S and at equilibrium total pressure in flask is 1.1 atm . If the equilibrium constant Kp for the reaction NH4HS(s) = NH3(g) + H₂S(g) represented as z × 10-¹ then find the value of is z.

A stationary x200 nucleus emits an a-particle with kinetic energy = 196 keV, if kinetic energy of daughter nucleus in this process is Kand Qvalue of the reaction is Qo, then

Choose correct option(s) using the given data of atomic masses. Energy released during a-decay of approximately The emission of proton from spontaneous Energy released during a-decay of 92238 is 4.25 MeV approximately The emission of proton from spontaneous

A wooden artifact from an ancient tomb contains 60 percent of the carbon-14 that is present in living trees. How long ago, to the nearest year, was the artifact made? (The half-life of carbon-14 is 5730 years.)

Identify the radioisotope used to determine the age of fossilized remains of an insect. C-14 Co-60 I-131 Na-24

Which of the following is emitted by an ideal medical tracer used for diagnostic purposes? I. Alpha rays II. Neutrons III. Gamma rays IV. X-rays I and III III and IV III alone IV alone

Which of the following dosages will best extend the shelf-life of strawberries? 30 kGY 0.3 kGy 3 kGy 13 kGy

Emissions from alpha decay require the least amount of shielding. Which best describes why the emissions from alpha decay are so easily blocked compared to the emissions of other types of radioactive decay? Alpha decay releases visible light, which has less energy than the light released during gamma decay. Alpha decay releases particles that have less mass and charge than the particles released during beta decay. Alpha decay releases particles that have less mass and charge than the particles released during gamma decay. Alpha decay releases particles that have more mass and charge than the particles released during beta decay.

20mg of radioactive substance loses 8% of its mass every minute. Because the substance becomes weaker, this is a "___".problem and can be modeled by the exponential function____.( After 10 minutes, the mass of the substance should be about___mg. rounded to the nearest whole number), and after minutes there will only be 2mg of the substance remaining (round the hours to the nearest 1/10). Blank 1: Blank 2: Blank 3: Blank 4:

A rare decay mode has been observed in which ²²²Ra emits a ¹⁴C nucleus. a. The decay equation is ²²²Ra → AX +¹⁴C. Identify Nuclide AX (element and number of nucleons) and explain your answer in a sentence.

The half-life of Lead-214 is 1584 s. (A) What is the decay constant for Lead-214? (B) A 100.0 kg sample of Lead - 214 is allowed to decay for 4752s. How many kg of Lead -214 remain after that time?

Put the following periods in correct order from Youngest to Oldest. Put the youngest at the top and place them in order to oldest at the bottom. = Triassic = Permian = Cretaceous =Jurassic = Cambrian =Ordovicia = Mississippian = Pleistocene = Devonian = Pre Cambrian

The initial value of the exponential function f (x) is 250 and is increasing by 4%. Which of the following statements about f (x) is true? (1 point) f(x) has a growth rate of 2.5 f(x) has a growth rate of 1.04 f(x) has a decay rate of 96% f(x) models exponential decay

A photon with energy 0.25MeV scatters off an electron that is at rest. The scattered photon is observed at an angle of 350 with respect to the incident photon. Determine the kinetic energy of the recoiling electron.

Naturally occurring strontium consists of four isotopes, Sr-84, Sr-86, Sr-87 and Sr-88, whose atomic masses are 83.9134, 85.9094, 86.9089 and 87.9056 amu respectively. The most abundant isotope is Sr-88 which accounts for 82.58% of naturally occurring strontium and the least abundant isotope is Sr-84 which accounts for 0.56% of naturally occurring strontium. Given that the observed atomic mass of strontium is 87.62 amu, calculate the percentages of Sr-86 and Sr- 87 in nature.