Which statement is true about the part of the electromagnetic spectrum that human eyes can detect?
a) it is divided into nine ranges of wavelengths.
b) it contains only the colors of the rainbow and television waves.
c) it contains ultraviolet, visible, and infrared light.
d) it is divided into seven ranges of wavelengths (visible light royg biv).

Wo audio speakers are placed on a vertical rail. speaker a is placed at head-level while speaker b is place at some variable height, \delta yδy, above speaker a. both speakers receive simultaneous input from a sine-wave generator so the speakers each produce a pure sinusoidal sound wave with a wavelength of 0.531 meters. calculate the lowest height that speaker b can be placed above speaker a to produce a minimum of sound heard by person standing \delta x = 7.86δx=7.86 meters directly in front of speaker a.

Ahydroelectric plant takes energy from water and turns it into electrical energy. what are the transformations of energy in the water molecules that are used in the process of generating electricity this way?

What is the average speed of a car that travels 40mph for 1 hour and 60 mph in another hour will mark brainliest