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
ArbitrLikvidat [17]
3 years ago
12

Sometimes a person cannot clearly see objects close up or far away. To correct this type of vision, bifocals are often used. The

top half of the lens is used to view distant objects and the bottom half of the lens is used to view objects close to the eye. A person can clearly see objects only if they are located between 34 cm and 180 cm away from his eyes. Bifocal lenses are used to correct his vision. What power lens (in diopters) should be used in the top half of the lens to allow him to clearly see distant objects
Physics
1 answer:
Alexxx [7]3 years ago
3 0

Answer:

The power of top half of the lens is 0.55 Diopters.

Explanation:

Since, the person can see an object at a distance between 34 cm and 180 cm away from his eyes. Therefore, 180 cm must be the focal length of the upper part of lens, as the top half of the lens is used to see the distant objects.

The general formula for power of a lens is:

Power = 1/Focal Length in meters

Therefore, for the top half of the lens:

Power = 1/1.8 m

<u>Power = 0.55 Diopters</u>

You might be interested in
In air, a sound wave with a frequency of 196 Hz has a wavelength of about 1.76 meters. What is the wavelength of a wave of the f
DENIUS [597]
I think the correct answer is B
3 0
3 years ago
There are 5510 lines per centimeter in a grating that is used with light whose wavelegth is 467 nm. A flat observation screen is
Mademuasel [1]

Answer:

1.696 nm

Explanation:

For a diffraction grating, dsinθ = mλ where d = number of lines per metre of grating = 5510 lines per cm = 551000 lines per metre and λ = wavelength of light = 467 nm = 467 × 10⁻⁹ m. For a principal maximum, m = 1. So,

dsinθ = mλ = (1)λ = λ

dsinθ = λ

sinθ = λ/d.

Also tanθ = w/D where w = distance of center of screen to principal maximum and D = distance of grating to screen = 1.03 m

From trig ratios 1 + cot²θ = cosec²θ

1 + (1/tan²θ) = 1/(sin²θ)

substituting the values of sinθ and tanθ we have

1 + (D/w)² = (d/λ)²

(D/w)² = (d/λ)² - 1

(w/D)² = 1/[(d/λ)² - 1]

(w/D) = 1/√[(d/λ)² - 1]

w = D/√[(d/λ)² - 1] = 1.03 m/√[(551000/467 × 10⁻⁹ )² - 1] = 1.03 m/√[(1179.87 × 10⁹ )² - 1] = 1.03 m/1179.87 × 10⁹  = 0.000848 × 10⁻⁹ = 0.848 × 10⁻¹² m = 0.848 nm.

w is also the distance from the center to the other principal maximum on the other side.

So for both principal maxima to be on the screen, its minimum width must be 2w = 2 × 0.848 nm = 1.696 nm

So, the minimum width of the screen must be 1.696 nm

4 0
3 years ago
a 0.0780 kg lemming runs off a 5.36 m high cliff at 4.84 m/s. what is its potential energy (PE) when it is 2.00 m above the grou
zmey [24]

Answer:

1.56 J

Explanation:

The potential energy only depends on the vertical height from the ground level.

We consider the ground level to have zero P.E.

So when it is 2 m above the ground level,

P.E. =  mgh

      = 0.078×10×2

      = 1.56 J

7 0
4 years ago
What are the four factors that determine weather?
garik1379 [7]
Solar Radiation, Orbital Distance, Air Pressure, and the Abundance of water.
8 0
3 years ago
This was observed in 1997 what is it
Tems11 [23]
It is a comet that was a comet

5 0
4 years ago
Read 2 more answers
Other questions:
  • Where are all stars bornWhat is the brightest star in the night sky? What is its magnitude?
    14·1 answer
  • Many animals use scent to _____.
    9·2 answers
  • if a star is 20 light minutes away and it stops creating light, how long will it be before we stop seeing the light?
    10·1 answer
  • Please help me please<br>​
    10·1 answer
  • Choose heated air or cooled air for the following atmospheric property term: rises
    5·1 answer
  • What are the properties of elements based on their placement on the periodic table?
    11·1 answer
  • How many types of protenies are there in all life as we know it
    13·1 answer
  • For a fixed voltage, the greater the electrical resistance, the less current will flow in a circuit.
    10·1 answer
  • Imagine you are in an open field where two loudspeakers are set up and connected to the same amplifier so that they emit sound w
    14·1 answer
  • What is the net force on this object A: 0 newtons b: 200 newtons c:400 newtons D:600 newtons
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!