Carl knows that water moves through different kinds of soil at different rates. how easily water moves through a soil is known as permeability. carl decides to compare the permeabilities of different soil types.

to do this, carl takes five identical flower pots with holes in the bottom and fills each one with different soil:
rocky, gravely dirt from the side of the road
potting soil from the store
clay soil from a nearby creek
sand from a store
dirt from his own backyard
carl pours one liter of water into each pot and measures how much water flows out of the bottom in one minute.

which of the following variables should be kept constant during this experiment?

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.