I know it’s a lot but please help, I have no idea what to do Photos are in order, sorry they are weirdly organised

Which compound is held together by the electrostatic force between two ions? a. co2 b. cci4 c. h2s d. mgf2

What sort of waves exhibit the doppler effect?

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c