3076

Physics Modern Physics Level: High School

Radioactivity

The half-life of 131-I is 8.04 days . Three days after it was prepared , its activity was 0.5 microCi, How many curies (in microCi) were initially prepared ?

a) 8.60

b) 3.70

c) 0.65

d) 0.055

e) 0.0039

2876

Physics Modern Physics Level: High School

Nuclear Fusion

One possible fusion reaction occurs when two deuterium nuclei combine to form nucleus of a helium atom. If the mass of each deuterium nucleus is 3.3444*10-27 kg and the mass of the helium nucleus is 6.6465*10-27 kg, how much energy is released when 1 kg of deuterium undergoes this fusion process ?

2513

Physics Modern Physics Level: High School

Radioactivity

A radioactive element decays according to the equation N(t) = N0 e-^3 t , where N0 is the original number of atoms , and N(t) is the number of atoms remaining after a time t measured in days . If N0 = 2 x e 7, find the time after which 2 x e 5 atoms remain .

2478

Physics Modern Physics Level: High School

Radioactivity

A radioactive element X decays to stable element Y . starting with a large pure sample of element X , after 5200 years the sample will be 81% element Y . the decay constant of element X is most nearly ( ) / yr .

2447

Physics Modern Physics Level: High School

Dual Nature

Calculate the energy of

(a) a photon of frequency 4.5 x 10^14 Hz .

(b) a photon of wavelength 6.0 x 10^-7 m

2440

Physics Modern Physics Level: High School

Nuclei

What is the binding energy per nucleon for tritium 3H which is the heaviest isotope of hydrogen ?

2437

Physics Modern Physics Level: High School

Radioactivity

A particle radioisotope has a half-life of 23.4 hours . At time t = 0, the activity is 6.90 x 10^9 Bq . Calculate the following .

a) The activity when t = 23.4 hours .

b) The time when activity will be reduced by a factor of 100 .

c) The value of the decay constant .

d) The original number of radioactive nuclei .

e) The number of radioactive nuclei at t = 23.4 hours .

2431

Physics Modern Physics Level: High School

Radioactivity

How much time is required before a 10 mCi sample of 99mTc (t ½ = 6.0 hours) and a 25 mCi sample of 113m In (t ½ = 1.7 hours ) possess equal activities ?

2111

Physics Modern Physics Level: High School

Nucleus

The half-life of carbon-14 is 5730 years . The time for ¾ of a sample of carbon-14 to decay is

a) 350 years

b) 2865 years

c) 11460 years

d) 17190 years

e) none of the above

2110

Physics Modern Physics Level: High School

Nucleus

The mass of an atom of helium-4(Z=2) is less than the mass of two free protons and two free neutrons because of ?

a) nuclear fusion

b) nuclear fission

c) neutron

d) nuclear emission

e) binding energy