Answer:

1. Frequency is defined as the number of vibrations per unit time and in one vibration one wave crest passes through a particular point. So the number of wave crests passing a given point per unit time is called frequency.

https://www.toppr.com/ask/question/the-number-of-wave-crests-passing-a-given-point-per-unit-time-is-given-by/

2. Electromagnetic Radiation

Electromagnetic radiation is a type of energy that is commonly known as light. Generally speaking, we say that light travels in waves, and all electromagnetic radiation travels at the same speed which is about 3.0 * 108 meters per second through a vacuum. We call this the "speed of light"; nothing can move faster than the speed of light.

A wavelength is one cycle of a wave, and we measure it as the distance between any two consecutive peaks of a wave. The peak is the highest point of the wave, and the trough is the lowest point of the wave.

https://lambda.gsfc.nasa.gov/product/suborbit/POLAR/cmb.physics.wisc.edu/tutorial/light.html#:~:text=Generally%20speaking%2C%20we%20say%20that,than%20the%20speed%20of%20light.

3. WAVE PARTICLE DUALITY

Evidence for wave-particle duality

Photoelectric effect

Compton effect

• Electron diffraction

• Interference of matter-waves

Consequence: Heisenberg uncertainty principle

https://slideplayer.com/slide/4178960/

4.What color absorbs most light?

Image result for The color that absorbs all light.

Black is the ultimate heat absorber. It absorbs all light on the visual spectrum, creating a void of light. As a result of absorbing all light wavelengths, black is the hottest possible color.

https://sciencing.com/colors-absorb-heat-8456008.html