all three questions please

In Young's double-slit interference experiment, it is found that the third dark fringe is at the angle of 19.5. If the separation between the double slits is 1.0103mm, find the wavelength (in m ) of the light source. Exponential format with 3 SF. QUESTION 23 What is the longest wavelength (in m ) of the EM radiation that can eject photoelectrons from a certain metal target, given that the binding energy is 6.07eV ? Exponential format with 3SF. QUESTION 24 When ultraviolet light with a wavelength of 334nm falls on a certain metal surface, the maximum kinetic energy of the emitted photoelectrons is measured to be 1.761019J. How much energy, in Joule, does an electron have to gain in order to escape from the metal surface? Exponential format with 3 SF. Click Save and Submit to save and submit. Click Save All Answers to save all answers