Please help :( I'm so confused.

Two plates of area 865 X 10'4 In2 each are separated by a distance of 31.9 X 10'2 m. Calculate the capacitance C of the capacitor. Structures on a bird feather act like a diffraction grating having 9000 lines per centimeter. What is the angle of the first-order maximum for 477 nm light shone through a feather? angle:The cockroach Periplaneta americana can detect a static electric field of magnitude 9.50 kN/C using their long antennae. If the excess static charge on a cockroach is modeled as point charges located at the end of each antenna, what magnitude of charge q would each antenna possess in order for each antennae to experience a force of magnitude 7.00 pN from the external electric field? Calculate a in units of nanocoulombs (nC). Enter numeric value 9 = nc