What Is Light? — Reading Comprehension

Light is the visible form of electromagnetic radiation that allows us to see the world around us. During a solar eclipse, the sudden blocking of sunlight makes the daytime sky dark. This dramatic change reveals how essential light is for vision, life, and technology. Scientists have spent centuries trying to understand what light truly is and how it behaves.

Properties and Nature of Light

Light is unique because it behaves as both a wave and a particle—a concept called wave-particle duality. As a wave, light travels in straight lines and can bend (refract) or bounce off surfaces (reflect). As a particle, it consists of photons, which are tiny packets of energy. Light moves extremely fast—about 299,792 kilometers per second (186,282 miles per second), making it the fastest thing in the universe. Unlike sound, which needs air or another medium to travel, light can move through the vacuum of space. This is why sunlight reaches Earth from the Sun, even though space is almost empty.

Sources and Applications of Light

There are two main types of light sources: natural and artificial. The Sun is the most important natural source, providing energy for photosynthesis and weather patterns. Other natural sources include stars and fireflies. Artificial sources, such as light bulbs and LED screens, are designed by humans to produce light for homes, streets, and electronic devices. Light is crucial for technologies like cameras, fiber optics, and medical instruments. For example, optical fibers use the property that light travels in straight lines to transmit internet data at nearly the speed of light.

How Light Enables Vision

Light is essential for vision. When light hits an object, it reflects in all directions. Our eyes collect some of these reflected rays, and the retina at the back of each eye senses the light. The retina sends signals to the brain, which processes them into images. The color of an object depends on which wavelengths of light are reflected and which are absorbed. Without light, vision is impossible because our eyes cannot detect anything in complete darkness. Scientists use this knowledge to design better lighting, develop vision-correcting technologies, and create safer environments.

Understanding the mechanisms of light has led to major advances in science and technology. From solar panels to digital cameras, the study of light shapes our world and connects to larger principles in physics.

Interesting Fact: A beam of light from the Sun takes about 8 minutes and 20 seconds to reach Earth, even though it travels at the fastest speed in the universe!

What is the definition of light according to the passage?

Which statement best describes how light travels?

What does 'wave-particle duality' mean?

Which of these is NOT a natural source of light?

What is the function of the retina in vision?

Which property allows light to reach Earth from the Sun?

According to the passage, why is light important for technology?

True or False: Light needs a medium like air or water to travel.

True or False: The color of an object depends on which wavelengths of light are reflected and absorbed.

What happens when there is no light?