Question

Physics help!!

Q 4

An object is placed 40 cm in front of a concave with a focal length of 20 cm. What is the magnification? -2.0 -1.5 -1.0 -2.5 -0.50 The total energy of a moving electron is 0.683 MeV. What is the speed of the electron in terms of c? 0.933 c 0.719 c 0.664 c 0.306 c The decay constant of a radioactive nuclide is 1.6 times 10^-3 s^-1. At a given instant, the number of atoms of the radioactive nuclide is 1.85 times 10^12. The number of atoms of the nuclide that remain after a time interval of 30 minutes is closest to: 1.26 times 10^11 1.38 times 10^11 1.14 times 10^11 1.04 times 10^11 1.52 times 10^11

Answer 1

Option D) is correct.

N(t) = No*exp[-decay constant*time] = 1.85*10^12*exp[-1.6*10^-3*30*60] = 1.04*10^11