Asample of radium-226 will decay to ¼ of its original amount after 3200 years. what is the half-life of radium-226?

years?

Describe the path of a ray that approaches a mirror parallel to the principal axis.

There are two-speed cameras, one in an are where the speed limit is 30 km/h and another where the speed limit is 50 km/h. in which will there be a smaller time interval between the photographs? explain your answer.

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?