What is the approximate wavelength of a light whose second-order dark band forms a diffraction angle of 15.0° when it passes through a diffraction grating that has 250.0 lines per mm? 26 nm 32 nm 414 nm 518 nm

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.