1.
What is the normal?
Correct Answer
A. The line perpendicular to the reflecting or refracting surface
Explanation
The normal is a line that is perpendicular to the reflecting or refracting surface. It is used to determine the angle of incidence and angle of reflection or refraction when waves interact with the surface. By drawing a line perpendicular to the surface at the point of interaction, it becomes easier to measure the angles accurately.
2.
What is the angle of incidence?
Correct Answer
A. The angle between the incident ray and the normal
Explanation
The angle of incidence is the angle between the incident ray (the incoming ray of light) and the normal (a line perpendicular to the surface at the point of incidence). It is an important concept in optics and is used to determine how light is reflected or refracted at a surface.
3.
What is the incident ray?
Correct Answer
A. The ray before it hits the surface
Explanation
The incident ray refers to the ray of light before it hits the surface. It is the ray that travels towards the surface and is incident upon it.
4.
What happens to the speed of light as it passes through a different medium?
Correct Answer
A. It changes speed
Explanation
As light passes through a different medium, such as air, water, or glass, it interacts with the atoms or molecules of that medium. This interaction causes the light to slow down, resulting in a change in its speed. This phenomenon is known as refraction. The change in speed of light is responsible for various optical effects, such as the bending of light when it enters a different medium at an angle.
5.
What happens when light is refracted?
Correct Answer
A. It refracts towards the normal
Explanation
When light is refracted, it changes direction as it passes from one medium to another. This change in direction is caused by the change in speed of light when it enters a different medium. The light waves bend towards the normal, which is an imaginary line perpendicular to the surface of the interface between the two mediums. Therefore, the correct answer is "It refracts towards the normal."
6.
What is a critical angle?
Correct Answer
A. The largest angle of incidence for which refraction can still occur
Explanation
The critical angle refers to the largest angle of incidence at which refraction can still occur. This means that if the angle of incidence exceeds the critical angle, total internal reflection will take place instead of refraction.
7.
When light passes through a denser medium it speeds up.
Correct Answer
B. False
Explanation
When light passes through a denser medium, it slows down, not speeds up. This is due to the interaction between the light waves and the particles in the medium. The particles in the denser medium cause the light waves to scatter and interact more, resulting in a decrease in speed. This phenomenon is known as refraction.
8.
What is total internal reflection?
Correct Answer
A. When light passing from a medium with a moderate refractive index into one with a low refractive index and completely reflects
Explanation
Total internal reflection occurs when light passes from a medium with a higher refractive index to one with a lower refractive index and is completely reflected back into the higher refractive index medium. This phenomenon happens when the angle of incidence is greater than the critical angle, causing the light to be reflected instead of refracted. Total internal reflection is commonly observed in situations such as light traveling from water to air, where the refractive index of air is lower than that of water.
9.
Light can be refracted and reflected at the same time.
Correct Answer
A. True
Explanation
Light can be refracted and reflected at the same time because refraction occurs when light passes from one medium to another and changes direction, while reflection occurs when light bounces off a surface. These two phenomena can happen simultaneously if light encounters a boundary between two media at an angle, causing both refraction and reflection to occur. This is commonly observed when light passes through a glass window, where some light is refracted as it enters the glass and some is reflected off the surface of the glass.
10.
What is a phenomenon that optical fibers uses?
Correct Answer
A. Total internal reflection
Explanation
Optical fibers use the phenomenon of total internal reflection. This occurs when light traveling through a denser medium, such as glass, reaches the boundary with a less dense medium, such as air, at an angle greater than the critical angle. Instead of refracting out of the medium, the light reflects back into the denser medium, allowing it to travel along the fiber by continuously reflecting off the inner walls. This property of total internal reflection enables optical fibers to efficiently transmit light signals over long distances with minimal loss or distortion.