Physics

Monochromatic light consists of waves of only one specific wavelength or color. A classic example is the yellow light from a sodium vapor lamp. Most light sources, like the sun or a bulb, produce a mix of many colors (polychromatic). In street lighting, monochromatic light is useful because it provides high contrast, though it does not show the true colors of objects well.

The boiling point is the temperature where a liquid turns into vapor. This temperature is not fixed; it changes with pressure. When you increase the pressure (like inside a cooker), the water molecules need more heat to escape. Thus, the boiling point rises. This allows the water to stay liquid at a higher temperature, which cooks the food faster. For example, at high altitudes, the pressure is low, so water boils at a lower temperature, and cooking takes longer.

There are two main types of curved mirrors: Concave and Convex. A Concave mirror curves inward (like a cave) and can magnify objects; it is used by dentists. A Convex mirror curves outward. It always forms a smaller, upright image. This is why it is used as a rear-view mirror in vehicles—it allows the driver to see a very large area of the road behind them in a small mirror.