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The half life of a radioactive substance is 3h and its activity is 1µCi. Then the activity after 9h will be (in µCi)
The correct answer is: 0.125
An electron positron pair (rest mass of each particle = 0.51 MeV) is produced by a γ ray photon of energy 2.42 MeV. The K.E. (in MeV) imparted to each of the charged particles shall be :
Rest mass energy + kinetic energy = energy of gamma photon
The correct answer is: 0.7
The probability of a radioactive atoms to survive 5 times longer than its half value period is.
Decay period = Half life × No. of half lives
The correct answer is: 0.03125
A radioactive nuclie decay as follows If mass number and atomic number of A are 180 and 72 respectively then atomic number for A_{4} will be.
_{72}A^{180} ^{α}>_{70}A_{1}^{176} ^{β}>_{71}A_{2}^{176} ^{α}>_{69}A_{3}^{172}^{γ}>_{69}A_{4}^{174}+γ
The correct answer is 69.
After emission of an α particle by a radioactive element _{84}X^{212}, the resulting mass number would be.
The correct answer is: 208
If the mass of proton = 1.008 amu and mass of neutron = 1.009 amu then binding energy (in MeV) per nucleon for _{4}Be^{9} (mass = 9.012 amu) would be :
Binding energy
The correct answer is: 6.72
After a time equal to four half lives, the percentage of radioactive material remaining undecayed is :
The correct answer is: 6.25
The halflife of cobalt 60 is 5.25 years. How long after a new sample is delivered, will the activity have decreased to about one third (1/3) of its original value. (Provide the time in years).
The correct answer is: 8.3
The mean life of a radioactive sample is 100 years. Then after 100 years, what percentage of the sample remains active.
The correct answer is: 37
10^{14} fissions per second are taking place in a nuclear reactor having efficiency 40%. The energy released per fission is 250 MeV. The power output (in Watts) of the reactor is :
Power output 0.4 x power input = 0.4 x 250 x 10^{6} x 1.6 x 10^{19} x 10^{14} = 1600W.
The correct answer is: 1600
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