D Question 23 7.5 pts A standing wave is oscillating at1600 Hz on a string, as shown in the figure. What is the wave speed? 60 cm 240 m/s 0 960 m/s 320 m/s O 480 m/s 0 640 m/sD Question 24 7.5 pts You are shaking the end of a string up and down to create a sinusoidal wave on the string, shown in the graph. Which of the graphs below represents the wave on the string when the tension in the string is decreased, but you continue to shake the end of the string up and down at the same rate? y (cm) Original y (cm) (a) y (cm) ( b ) y (cmm) (c) (d) O d O a ob OC KThis exam consists of I True/ raise question (1 pont) and points each). D Question 25 7.5 pts Light of wavelength 400 nm bombards a surface with work function 2.46 eV. What is the maximum kinetic energy of the photoelectrons from this surface? O 2.46 eV 0 0.840 eV O No photoelectrons are emitted. 0 0.640 eV Next