Astructural steel column is 20 meters long and has a square cross-section with a side length of 10 cm. a force of 6 × 105 newtons compresses the column. (this force is equivalent to the weight of several trucks.) estimate by how much the column’s length decreases, and compare the change in length with the original length of the column. first, divide the force by the cross-sectional area to calculate the stress σ. when you calculate the area, remember to convert to meter2. then use the equation to calculate the change in length, δl. show the steps in your work.

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.