A painter and his helper are standing on a scaffold. The painter weighs 400 newtons. The helper weighs 300 newtons. The tension in a rope A is 925 newtons. The tension in rope B is 825 newtons. What Is the weight of the board?

Which statement is true about the model of the electromagnetic spectrum a: it change the frequencies of light. b: it compare wavelengths of light. c: the color of light waves can be changed using the model. d: the intensities of light waves can be decreased using the model.