1B23 MODERN PHYSICS, ASTRONOMY AND COSMOLOGY
NUMERICAL ANSWERS TO 1997 PHYSICS EXAM QUESTIONS
N/A
First shell (n=1): 2 electrons. Second shell (n=2): 8 electrons. Third shell (n=3): 18 electrons.
Invariant interval l^2 = x^2 + y^2 + z^2 - c^2 t^2
6.583 x 10^-8 seconds
Wavelength = 0.0173 nm; spacing d = 0.328 x 10^-10 m
Brother's age 18.72 years, sister's age 13.08 years. [N.B. Special relativity is not now included in 1B23.]
Wavelength must be a few fm, so energy ~ 1GeV.