In which of the following situations is the photoelectric effect being demonstrated? A.
An electron within an atom absorbs energy when it is hit by a photon and jumps to a higher energy level within the atom.
B.
An electron moves through a sea of electrons within a block of aluminum atoms when a voltage is applied to the metal.
C.
A photon of light travels at the speed of light in a vacuum but moves slightly slower through a medium made of matter.
D.
The color of a substance is determined by the wavelength of electromagnetic radiation that is reflected off of its surface

Which of the following statements does not explicitly describe a transfer of money a. a ball dropped from a heigh hits the ground with a high speed. b. the collision produced in a nuclear reaction heat up the surroundings. c. a plane increases its air speed from 150 mi/hr to 200 mi/hr. d. the electricity from the power socket causes the fan to turn.

Lymphocytes known as blastocysts make antibodies that fight infection. select the best answer from the choices provided t f

The inside surface of a cylindrical-shaped cave of inner diameter 1.0 m is continuously covered with a very thin layer of water. the cave is very long and it is open on both ends. the water on the cave surface is at a constant temperature of 15.5 °c. the cave is constantly exposed to wind such that 15.5 °c air flows through the cave at 4.5 m/s. the kinematic viscosity of the air is 14.66 x 10-6 m2/s and the molecular diffusion coefficient of water vapor in the air is 0.239 x 10-4 m2/s. because the cave diameter is so large, the flow of wind down the length of the cave, in the x direction, can be treated like it is external flow and the cave surface can be approximated as flat where appropriate. calculate the x value, in a) the transition to turbulent flow occurs at rex meters, where the air flow transitions from laminar to turbulent along the inside surface of the cave b) calculate the x value, in meters, where the bulk steady state concentration of water vapor in the air flowing in the cave is 10% of the saturation concentration. assume the air at the surface of the water layer is 100% saturated with water vapor. assume the wind entering the cave contained no moisture before it entered the cave. take into account the transition from laminar to turbulent flow when solving part b