Asmall metal bar, whose initial temperature was 20°c, is dropped into a large container of boiling water. how long will it take the bar to reach 90°c if it is known that its temperature increases 2°in 1 second? how long will it take the bar to reach 98°c?

Which theory was contradicted by experiments with the photoelectric effect? light spreads out after it passes through a small opening. as soon as light strikes metal, electrons will be ejected. visible light, regardless of color, will cause the ejection of electrons when striking metal. the kinetic energy of ejected electrons depends on the frequency of light that strikes the metal.