1) D
2) D.) Greater than
Explanation:
1)
The phenomenon of total internal reflection occurs when a ray of light hitting the interface between two mediums is totally reflected back into the original medium, therefore no refraction into the second medium occurs.
This phenomenon occurs only if two conditions are satisfied:
- The index of refraction of the first medium is larger than the index of refraction of the 2nd medium
- The angle of incidence is greater than a certain angle called critical angle
In picture 1, we have 4 different diagrams. In the diagrams:
- The red arrow represents the incident ray
- The green arrow represents the refracted ray
- The blue arrow represents the reflected ray
Total internal reflection occurs when there is no refraction, therefore when there is no green arrow: this occurs only in figure D, so this is the correct option. (in figure C, there is a refracted ray but it is parallel to the interface: this condition occurs when the angle of incidence is exactly equal to the critical angle, however in this problem, the angle of incidence is greater than the critical angle, so the correct option is D)
2)
As we stated in problem 1), total internal reflection occurs when the angle of incidence is equal or greater than the critical angle. Therefore in this case, the angle of incidence must be
D.) Greater than
There are no true statements on the list you attached.
Answer:
Option B: change the objective lens
Explanation:
The revolving nosepiece is one of the parts of a microscope. Its responsibility is to hold the objective lenses.
A). 6,000 Hz.
No. This is in the middle of the human hearing range. If a radio station were transmitting on this frequency, then every wire and cable in town would pick up a little of its energy, and you'd hear it on every telephone, earbud, and headphone, and it would come out of every loudspeaker.
B). 6,000,000 Hz. (6 mHz)
No. This isn't used by 'commercial' broadcasting stations, but it IS used by
foreign short-wave stations, to broadcast news, 'culture', and propaganda
into other countries.
C). 60 Hz.
No. This is the frequency of the AC that you use when you plug anything
into a wall socket. All of the electric company's power lines RADIATE a
little bit of energy at this frequency, so it wouldn't be a very smart frequency
for a radio station to try to use, since the whole country is already blanketed
with interference at this frequency.
D). 600,000 Hz (600 kHz)
Yes ! This is the "600" or "60" or "6" that's marked
near the left end of your AM radio dial.
yay !