Test: Light - Class 6 MCQ

Scattering occurs when light hits tiny dust particles in the air and is sent in different directions. This phenomenon allows us to see objects that are not directly in the path of the light source, especially during times like dusk or dawn.

The length of a shadow changes depending on the distance of the light source from the object. As the sun moves across the sky, its position alters the angle and distance from which light hits the object, resulting in variations in shadow length throughout the day. Shadows are longest when the sun is low in the sky and shortest when it is directly overhead.

Shadows are always formed on the opposite side of the light source. When an object blocks light, the area behind it where light cannot reach creates a shadow. The shape of the shadow corresponds to the outline of the object blocking the light.

Animals use bio-luminescence for various purposes, such as attracting prey, communicating with others, and sometimes for camouflage. This natural light production is a fascinating adaptation that serves multiple functions in the animal kingdom.

A convergent beam of light occurs when multiple rays come together at a single point. This can be observed when light passes through a magnifying lens, where it focuses light onto a specific spot.

A total solar eclipse occurs when the moon completely obscures the sun from view, casting a shadow on the Earth. This can only happen during a new moon when the moon is positioned directly between the Earth and the sun.

Transparent materials allow light to pass through completely, enabling clear visibility through them. Examples include glass and water. In contrast, opaque materials do not allow light to pass at all, and translucent materials allow only some light through, resulting in a foggy appearance.

The penumbra is the lighter, outer region of a shadow where some light still reaches. In contrast, the umbra is the darkest part of the shadow where no light can penetrate. The penumbra creates a gradient effect around the shadow.

When the light source is moved closer to the object, the shadow becomes larger and fuzzier because the light rays diverge more as they travel from the source to the object, creating a larger area of darkness behind the object.

Without a light source, there can be no shadows. Shadows are formed when light is blocked by an opaque object; in darkness, there is no light to cast a shadow, making them invisible.

A screen is used in shadow experiments to visualize the shadow cast by an object blocking light. The screen provides a surface where the absence of light due to the obstruction can be seen as a dark area, allowing for a clear demonstration of shadow formation.

Rectilinear propagation of light refers to the property of light to travel in straight lines through any medium, such as air or water. This principle is fundamental to understanding how light behaves and is crucial in optics.

The sun is categorized as a natural source of light because it is created by nature. In contrast, torches, candles, and LED bulbs are artificial sources made by humans. Natural sources like the sun are essential for life on Earth.

A lunar eclipse happens when the Earth is positioned directly between the sun and the moon, causing the Earth's shadow to fall on the moon. This results in the moon becoming obscured and can only occur during a full moon when the moon is fully illuminated.

Luminous objects are those that emit their own light, such as the sun and stars. In contrast, transparent objects allow light to pass through without scattering, while translucent objects partially allow light through, and opaque objects block light entirely.

When an object is closer to the light source, the shadow tends to be larger and fuzzier. Conversely, as the object moves closer to the screen where the shadow is cast, the shadow becomes sharper and more defined, illustrating how the position of the object and light source affects shadow clarity.

A divergent beam of light occurs when light rays spread out from a small source, such as a candle. The light emanates in various directions, creating a wide beam, as opposed to converging or remaining parallel.

A pinhole camera creates images by allowing light to pass through a tiny hole. This simple device demonstrates the principle of light traveling in straight lines, resulting in an inverted image on the screen inside the camera.

Bio-luminescence is the light produced by living organisms through chemical reactions within their bodies. Unlike artificial light sources, which are man-made, bio-luminescent organisms, such as fireflies, generate their own light for various purposes, including attracting mates.

Non-luminous objects do not produce their own light; they become visible by reflecting light that falls on them from luminous sources. For example, when sunlight or light from a bulb hits a table, the light reflects off the surface and enters our eyes, allowing us to see the table.