Suppose that 5 J of work is needed to stretch a spring from its natural length of 36 cm to a length of 45 cm. Required:
a. How much work is needed to stretch the spring from 38 cm to 43 cm? (Round your answer to two decimal places.) J
b. How far beyond its natural length will a force of 45 N keep the spring stretched? (Round your answer one decimal place.

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.