The scanning-tunneling microscope works on the principle of electron tunneling. imagine you are trying to optimize your scanning tunneling microscope. your microscope has a gold tip (work function = 5.1 ev) and your electron has a kinetic energy of 4.6 ev (a) if you move the tip to sample distance from 0.3 nm to 0.2nm how does the transmission probability change? (b) you have a “brilliant” idea. what if you use protons instead of electrons? how will the transmission probability change?

An incident ray through the focal point of a spherical mirror will: reflect through the center of curvature. reflect back through the focal point. reflect parallel to the principle axis. reflect the same direction as the incident ray.

The items in the following list are all units of matter. which is the smallest unit that retains the properties of the matter? a.) atom b.) compound c.) electron d.) element

Emmy kicks a soccer ball up at an angle of 45° over a level field. she watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. consider only the time that the ball is in the air, after being kicked but before landing. take "north" and "up" as the positive ‑ and ‑directions, respectively, and use ≈10 m/s2 for the downward acceleration due to gravity.