Which best compares AC and DC?

a
AC flows in one direction, and DC repeatedly switches direction.
b
AC is used only in generators, and DC is used only in motors.
c
DC is used only in generators, and AC is used only in motors.
d
DC flows in one direction, and AC repeatedly switches direction.

Surface currents are caused by blank space . question 14 options: surface currents are caused by? differences in water temperature high salinity differences in density wind forces

Astudent completes a titration by adding 12.0 milliliters of naoh(aq) of unknown concentration to 16.0 milliliters of 0.15 m hcl(aq). what is the molar concentration of the naoh(aq)? 1)5.0 m 2)0.20 m 3)0.11 m 4)1.1 m

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?