1.
Which statement explains why a pencil looks broken when placed in a cup of water?
Correct Answer
A. Light is refracted as it moves from air to water
Explanation
When light travels from one medium to another with a different refractive index, such as air to water, it undergoes refraction. Refraction is the bending of light as it passes through the boundary between two different mediums. In this case, when the pencil is placed in a cup of water, the light rays from the pencil pass through the air-water boundary and are refracted. This bending of light causes the rays to change direction, resulting in the pencil appearing broken or distorted when viewed through the water.
2.
Light travels in a _____________.
Correct Answer
B. Straight line.
Explanation
Light travels in a straight line. This is because light is a form of electromagnetic radiation that travels in a continuous path called a ray. In a vacuum or a medium with a uniform refractive index, light rays travel in straight lines. This phenomenon is known as rectilinear propagation of light. However, when light encounters a medium with a different refractive index or undergoes diffraction or reflection, its path may appear curved or deviated, but it still travels in straight line segments between these points of interaction.
3.
A frosted window is ____________.
Correct Answer
B. Translucent.
Explanation
A frosted window would be translucent because it allows some light to pass through but scatters it, making the objects on the other side blurry or unclear.
4.
When light bounces off a smooth, shiny surface, what process has occurred?
Correct Answer
B. Reflection
Explanation
When light bounces off a smooth, shiny surface, the process that has occurred is reflection. This is because the light waves hit the surface and bounce back in the opposite direction without changing their direction or speed. Refraction refers to the bending of light as it passes through different mediums, transmission refers to the passage of light through a substance, and photosynthesis is the process by which plants convert light energy into chemical energy.
5.
How is a rainbow formed?
Correct Answer
D. Light rays bend as they pass from air through drops of water.
Explanation
When light passes through drops of water in the air, it undergoes a process called refraction. This means that the light rays change direction as they pass from one medium (air) to another (water). As a result of this refraction, the different colors of light separate and spread out, forming a spectrum. This spectrum is what we perceive as a rainbow. Therefore, the correct answer is that light rays bend as they pass from air through drops of water.
6.
What happens when a material absorbs light?
Correct Answer
A. Light energy is changed into heat energy.
Explanation
When light strikes a material and is absorbed, its energy is transferred to the atoms or molecules within that material. This energy is used to excite the electrons in the atoms or molecules, causing them to move to higher energy levels or become more energetic. As a result of this increased energy, the atoms and molecules start to vibrate more vigorously, and this vibrational motion is a manifestation of heat energy.
In simpler terms, think of absorbed light as packets of energy being "captured" by the material. This captured energy raises the internal temperature of the material because the atoms or molecules are now moving more rapidly, creating what we perceive as heat.
So, when a material absorbs light, it essentially transforms the incoming light energy into thermal (heat) energy within the material, leading to an increase in temperature. This is a fundamental process that occurs in various contexts, from sunlight warming the Earth's surface to the absorption of light by objects in our daily lives.
7.
We can see objects mainly because they __________.
Correct Answer
C. Reflect light
Explanation
Objects are visible to us because they reflect light. When light falls on an object, it interacts with its surface. Some of the light is absorbed by the object, but a significant portion is reflected back towards our eyes. This reflected light carries information about the object's color, texture, and shape, allowing us to perceive and see the object. Therefore, the ability of objects to reflect light is the main reason why we can see them.
8.
In what way is a mirror different from a stop sign?
Correct Answer
A. The light (and all colors) bounce off the mirror.
Explanation
A mirror is different from a stop sign because when light hits a mirror, it reflects off the surface and bounces back, allowing us to see our reflection. In contrast, a stop sign does not reflect light in the same way. Instead, it absorbs and scatters light, which is why we see it as a solid color.
9.
Which object scatters light rays as they pass through it?
Correct Answer
C. Translucent object
Explanation
A translucent object scatters light rays as they pass through it. Unlike transparent objects that allow light to pass through without scattering, and opaque objects that do not allow light to pass through at all, translucent objects partially transmit light while also causing it to scatter. This scattering of light results in a blurred or diffused appearance, making it difficult to see objects clearly through the translucent material.
10.
What causes a blue block to appear blue in the sunlight?
Correct Answer
C. Only blue light is reflected by the block.
Explanation
The correct answer is that only blue light is reflected by the block. This means that when sunlight hits the block, all the other colors of light are absorbed by the block, while the blue light is reflected back to our eyes. This reflection of blue light is what causes the block to appear blue in the sunlight.