Olympiad Test: Light, Shadows And Reflection - 1 - Class 6 MCQ

Light is produced by luminous objects, which are objects that emit their own light, such as the Sun, stars, or light bulbs. Non-luminous objects do not emit light but can reflect light from luminous objects. Transparent objects allow light to pass through them, and opaque objects block light from passing through.

The size and direction of shadows change throughout the day because the position of the Sun in the sky changes. In the morning and evening, the Sun is lower in the sky, creating longer shadows. At midday, when the Sun is higher in the sky, the shadows are shorter. This change happens due to the apparent movement of the Sun across the sky.

- When a letter is viewed in an ordinary plane mirror, it undergoes a lateral inversion, meaning it is flipped horizontally.
- The capital letter "R" in a mirror will have its right side become the left and vice versa.
- Option B shows the letter "R" flipped horizontally, which is the correct mirrored image.
- Lateral inversion does not change the vertical orientation, so the top and bottom remain unchanged.
- Therefore, the correct mirrored appearance of "R" is as shown in option B.

The image of an object formed in water is typically erect (upright). This happens because water, acting like a plane mirror, forms an image of the object that is similar to the actual object, and the image is upright (not inverted) as long as the object is placed above the water surface. The image may appear to be diminished or distorted in some cases depending on the angle of viewing, but it is typically erect.

- Ishani observes the sun's position changing because of the Earth's rotation.
- The Earth rotates on its axis from west to east, completing a full rotation in about 24 hours.
- This rotation causes the sun to appear to rise in the east, move across the sky, and set in the west.
- This daily movement gives us day and night.
- The rotation of the Earth, not its revolution around the sun or any other celestial body, is responsible for this observation.

- To form a circular shadow, an object must have a circular cross-section when light is shone onto it.
- A CD and a ball both have circular cross-sections, so they can form circular shadows.
- An ice-cream cone can cast a circular shadow if the light hits its base perpendicularly.
- A shoe box, with its rectangular shape, will predominantly cast rectangular or elongated shadows, not circular ones.
- Therefore, a shoe box (B) will not form a circular shadow.

- A solar eclipse occurs when the moon comes between the sun and the earth, aligning in a straight line.
- This alignment causes the moon to cast a shadow on the earth.
- The shadow forms because the moon blocks the sunlight from reaching certain parts of the earth.
- The dark inner part of the shadow, where the sun is completely obscured, is called the umbra, and the outer part, where the sun is partially seen, is the penumbra.
- Thus, the correct answer is B: Formation of a shadow of the moon on the earth.

- In a completely dark room, there is no source of light.
- Mirrors reflect light to form images, but without any light, reflection cannot occur.
- Since visibility requires light to enter the eyes, and the mirror needs light to reflect an image back to you, no image will be seen in total darkness.
- Therefore, in complete darkness, holding a mirror in front of you will result in seeing nothing, leading to the correct answer: D: No image.

- Sanchit's experiment shows that light travels in a straight line by using a flashlight and a cardboard with a small hole.
- The light passing through the hole forms a narrow, straight beam, illustrating that light doesn't bend around obstacles.
- This behavior of light is known as the rectilinear propagation of light.
- Both statements A and B are correct and describe the same phenomenon.
- Therefore, the conclusion is option C: "A and B both."

Butter Paper is an example of a translucent object.

• Butter Paper is considered translucent since it allows light to travel partially through it.
• It has a fainter shadow and it lets light pass through it.
• Translucent objects are objects through which light is able to pass, but through which objects are not clearly visible.
• The examples of translucent objects are wax paper or frosted glass-like one might find in a shower.
• Opaque is not capable of having light pass through.

The phenomenon where your left hand appears as your right hand in a plane mirror is called lateral inversion. In lateral inversion, the left and right sides of an object are reversed when reflected in a mirror, although the top and bottom remain unchanged. This is why your left hand appears as your right hand in the mirror.

Shadows are formed when something comes into the path of light through which light rays couldn 't pass as light travels in straight line (or rectilinear propagation). It forms on the opposite side of the light source.

• Sanchit's Statement: Correct. Light is energy that enables us to see objects, but light itself is not visible.
• Ananya's Statement: Correct. A pin-hole camera produces an inverted image due to light rays crossing at the aperture.
• Ruhi's Statement: Incorrect. The moon is not luminous; it reflects sunlight, which makes it visible.
• Rohit's Statement: Correct. Periscopes use plane mirrors to reflect light, allowing observation over obstacles.

Thus, Ruhi's statement is incorrect because the moon reflects light rather than emitting it.

Correct option is A.  Both B and C are correct

1. The colour of shadow does not depend on the colour of the object. The shadow is always black in colour. So, all three towels will form same colour shadow.
2. The colour of shadow does not depend on the colour of the object, it depends on the thickness of the object. The shadow is always black in colour. So, all three towels will form same colour shadow

A pinhole camera is a simple camera without a lens but with a tiny aperture, a pinhole camera – effectively a light-proof box with a small hole in one side. Light from a scene passes through the aperture and projects an inverted image on the opposite side of the box, which is known as the camera obscura effect.

Reflection is the phenomenon by which any incident light falling on a surface is sent back into the same medium where it originated.

So correct answer is reflection.

The ability of an object to reflect light depends on its smoothness. A smoother surface reflects light more effectively, resulting in a clearer and more defined reflection. If object A reflects more than object B, it is likely to have a smoother surface than object B. Rougher surfaces scatter light in different directions, making them less reflective.

A translucent object allows only some light to pass through it, which causes a faint glow or diffused light to be visible, but not a clear image of the light source (like the torch). This is different from transparent objects, which allow light to pass through clearly, and opaque objects, which block all light.

At night, the Moon and the stars are the primary natural sources of light in the sky. The Moon reflects sunlight, while stars emit their own light. Clouds, however, do not emit light, though they may reflect light from the Moon or artificial sources, which is why they can sometimes appear illuminated. But the actual sources of light in the night sky are the Moon and stars.

The color of a shadow is typically black because it is formed in the absence of light. The color of the object casting the shadow (in this case, the green ball) does not affect the shadow's color. Shadows appear black or grey because they are regions where the light is blocked by the object, preventing light from reaching that area.