1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Anton [14]
3 years ago
12

Suppose a ray of light traveling in a material with an index of refraction n a reaches an interface with a material having an in

dex of refraction n b . Which of the following statements must be true for total internal reflection to occur?
Check all that apply.A. The angle of incidence must be less than the critical angle.B. na = nbC. na > nbD. The angle of incidence must be greater than the critical angle.E. The angle of incidence must be equal to the critical angle.
Physics
1 answer:
KATRIN_1 [288]3 years ago
5 0

Answer: C and D

Explanation: One of the first rule for total internal reflection to occur is that the ray must move from a dense to a less dense medium, hence refractive index of medium a must be greater than that of b.

When a ray moves from a dense to a less dense medium, the refracted ray moves away from the normal thus increasing the size of the angle of refraction (total internal refraction occurs when the angle of refraction is 90° and the angle of incidence at this point is known as the critical angle), hence the angle of incidence must be greater than the critical angle.

These points verifies option C and D

You might be interested in
Chứng minh mặt trời là nguồn gốc của tất cả nguồn năng lượng
Hatshy [7]

An Excerpt from “Optimism”

by Helen Keller

1 Could we choose our environment, and were desire in human undertakings synonymous with

endowment, all men would, I suppose, be optimists. Certainly most of us regard happiness as

the proper end of all earthly enterprise. The will to be happy animates alike the philosopher, the

prince and the chimney-sweep. No matter how dull, or how mean, or how wise a man is, he feels

that happiness is his indisputable right.

2 It is curious to observe what different ideals of happiness people cherish, and in what singular

places they look for this well-spring of their life. Many look for it in the hoarding of riches, some

in the pride of power, and others in the achievements of art and literature; a few seek it in the

exploration of their own minds, or in the search for knowledge.

3 Most people measure their happiness in terms of physical pleasure and material possession.

Could they win some visible goal which they have set on the horizon, how happy they would be!

Lacking this gift or that circumstance, they would be miserable. If happiness is to be so

measured, I who cannot hear or see have every reason to sit in a corner with folded hands and

weep. If I am happy in spite of my deprivations, if my happiness is so deep that it is a faith, so

thoughtful that it becomes a philosophy of life,—if, in short, I am an optimist, my testimony to

the creed of optimism is worth hearing....

4 Once I knew the depth where no hope was, and darkness lay on the face of all things. Then

love came and set my soul free. Once I knew only darkness and stillness. Now I know hope and

joy. Once I fretted and beat myself against the wall that shut me in. Now I rejoice in the

consciousness that I can think, act and attain heaven. My life was without past or future; death,

the pessimist would say, “a consummation devoutly to be wished.” But a little word from the

fingers of another fell into my hand that clutched at emptiness, and my heart leaped to the

rapture of living. Night fled before the day of thought, and love and joy and hope came up in a

passion of obedience to knowledge. Can anyone who has escaped such captivity, who has felt

the thrill and glory of freedom, be a pessimist?

5 My early experience was thus a leap from bad to good. If I tried, I could not check the

momentum of my first leap out of the dark; to move breast forward is a habit learned suddenly

at that first moment of release and rush into the light. With the first word I used intelligently, I

learned to live, to think, to hope. Darkness cannot shut me in again. I have had a glimpse of the

shore, and can now live by the hope of reaching it.

6 So my optimism is no mild and unreasoning satisfaction. A poet once said I must be happy

because I did not see the bare, cold present, but lived in a beautiful dream. I do live in a

beautiful dream; but that dream is the actual, the present,—not cold, but warm; not bare, but

furnished with a thousand blessings. The very evil which the poet supposed would be a cruel

6) Read the last sentence from the text.

Only by contact with evil could I have learned to feel by contrast the beauty of truth and love and goodness.

Explain how Helen Keller develops this idea in the text. Use specific details to

support your answer.

8 0
3 years ago
Density=2g/mL and volume=20mL what is mass
leva [86]

Answer:

40g

Explanation:

Mass = density x volume

= 2 x 20

= 40g

8 0
3 years ago
Read 2 more answers
A baseball pitcher throws a ball at 90.0 mi/h in the horizontal direction. How far does the ball fall vertically by the time it
Lisa [10]

Answer:

Vertical distance=  3.3803ft

Explanation:

First with the speed of the ball and the distance traveled horizontally we can determine the flight time to reach the plate:

Velocity= (90 mi/h) × (1 mile/5280ft) = 475200ft/h

Distance= Velocity × time⇒ time= 60.5ft / (475200ft/h) = 0.00012731h

time=  0.00012731h × (3600s/h)= 0.458316s

With this time we can determine the distance traveled vertically taking into account that its initial vertical velocity is zero and its acceleration is that of gravity, 9.81m/s²:

Vertical distance= (1/2) × 9.81 (m/s²) × (0.458316s)²=1.0303m

Vertical distance= 1.0303m × (1ft/0.3048m) = 3.3803ft

This is the vertical distance traveled by the ball from the time it is thrown by the pitcher until it reaches the plate, regardless of air resistance.

3 0
3 years ago
How is work calculated?
BartSMP [9]

Work is force times distance. If there's no distance, there's no work being done.

6 0
3 years ago
A fossil form when an organism buried in sediment dissolves leaving a hollow area
IceJOKER [234]

Answer:

A Mold

Explanation:

A mold forms when hard parts of an organism are buried in sediment; the hard parts completely dissolve over time, leaving behind a hollow area. A cast forms as a result of a mold when minerals and sediment fill in the impression.

3 0
3 years ago
Other questions:
  • A square coil (length of side = 24 cm) of wire consisting of two turns is placed in a uniform magnetic field that makes an angle
    15·1 answer
  • NEED THIS ANSWERED ASAP!!!! IN MIDDLE OF TEST RN HELP PLZ
    9·2 answers
  • A typical 12-V car battery can deliver about 750,000 C of charge before dying. This is not a lot of charge. As a comparison, cal
    6·1 answer
  • Needing help with this please
    10·1 answer
  • What two aspects of a force do scientists measure?
    15·1 answer
  • In which type of process is a gas heated so rapidly that is expands before any heat can escape, resulting in an absence of heat
    9·1 answer
  • Which organism contains organ systems?
    5·1 answer
  • Is time a <br><br> vector,<br> scalar,<br> both,<br> neither
    15·1 answer
  • 1 poi
    5·1 answer
  • A body falls from rest under gravity, the velocity “v” is given by v=kgp h q , where h is the distance fallen through, g the acc
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!