Atomic and Nuclear Physics Answers

why neutron has no charge?

calculate how long it would take for the following to decay to an activity of 1 becquerel (Bq).
1. A sample of cobalt-60(half-life - 5.27 years) whose original activity is 64 Bq.
2.A sample of iodine-131 (half-life - 8 days) whose original activity is 128 Bq.
3. A sample of polonium -210 (half-life - 138 days) whose original activity falls is 32 Bq.

calculate the half lives of the following samples.
1. A sample of iodine-123 whose activity falls from 1000 Bq to 250 Bq in 14.4 hours.
2.A sample of technetium -99m whose activity falls from 200 Bq to 25 Bq in 18 hours.
3. A sample of strontium-90 whose activity falls 500 Bq to 62.5 Bq in 86.4 years.

To resolve an object in an electron microscope, the wavelength of the electrons must be close to the diameter of the object. What kinetic energy must the electrons have in order to resolve a protein molecule that is 4.20 nm in diameter? Take the mass of an electron to be 9.11× 10–31 kg.

calculate how thick an absorber needs to be absorbed half of the incoming ligh

calculate the instantaneous speed of an apple that falls freely from a rest position and accelerates at 10m/s^2 for 1.5 seconds

Calculate the mass defect and binding energy per nucleon for a lithium nucleus (3 7 Li):
Mass of lithium nucleus (M) = 7.000000 u
Mass of proton (mp) = 1.007825 u
Mass of neutron (mn) = 1.008665 u
1 u = 931 MeV

If an object has an initial position
(x1, y1) = (5.0 m, 9.0 m),
and an initial velocity
(v1x, v1y) = (2.0 m/s, −9.0 m/s),
what is the final position vector
(x2, y2)
of the object if its two-dimensional acceleration is described by the graphs in the figure below? (Express your answer in vector form in metres.)

explain double diffraction

1. a) Calculate the ionisation energy of rubidium per atom, if light of wavelength 5.84 x 10 raised to the power of -8 m produces electrons with a speed of 2.450 x 10 raised to the power of 6 m/sec.
[Hint: Assume that the threshold frequency refers to the frequency corresponding to the ionisation energy.]


b) Assume that the electron in Li raised to the power 2+ ion is in third orbit. Calculate
i) the radius of the orbit and,
ii) the total energy of the electron.

[Hint: Li raised to the power 2+ ion also has atomic spectra similar to hydrogen atom. While applying relevant equations, use Z = 3.]