22. White noise is ... a very loud sound

a single frequency at the same time

a very quiet sound

a whole bunch of frequencies at the same time​

Adouble-slit experiment is performed with light of wavelength 600 nm. the bright interference fringes are spaced 1.8 mm apart on the viewing screen.what will the fringe spacing be if the light is changed to a wavelength of 400 nm? ?

Two forces produce equal torques on a door about the door hinge. the first force is applied at the midpoint of the door; the second force is applied at the doorknob. both forces are applied perpendicular to the door. which force has a greater magnitude?

An important dimensionless parameter concerned with very high-speed flow is the mach number, defined as v/c, where v is the speed of the object such as an airplane or projectile, and c is the speed of sound in the fluid surrounding the object. for a projectile traveling at 1170 mph through air at 50 ˚f and standard atmospheric pressure, what is the value of the mach number?