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3 years ago

What causes short sightedness ?how is it corrected

Physics

1 answer:

7nadin3 [17]3 years ago

5 0

Answer:

Short sight occurs when the eyeball is too long or the lens is too thick, or both. As a result, light rays from distant objects are focused in front of the retina (because the light rays are highly converged). The image formed on the retina is therefore out of focus.

Short sight can be corrected by wearing glasses with concave lenses. Light rays from distant objects are diverged by concave lenses before entering the eyes, so that light can be focused on the retina to form a sharp image.

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Light travels faster in warmer air. On a sunny day, the sun can heat a road and create a layer of hot air above it. Let's model

AysviL [449]

Answer:

Explanation:

If we assume there is a sharp boundary between the two masses of air, there will be a refraction. The refractive index of each medium will depend on the relative speeds of light.

n = c / v

If light travels faster in warmer air, it will have a lower refractive index

nh < nc

Snell's law of refraction relates angles of incidence and refracted with the indexes of refraction:

n1 * sin(θ1) = n2 * sin(θ2)

sin(θ2) = sin(θ1) * n1/n2

If blue light from the sky passing through the hot air will cross to the cold air, then

n1 = nh

n2 = nc

Then:

n1 < n2

So:

n1/n2 < 1

The refracted light will come into the cold air at angle θ2 wich will be smaller than θ1, so the light is bent upwards, creating the appearance of water in the distance, which is actually a mirror image of the sky.

6 0

3 years ago

If there was a small sphere freely suspended in plane poiseuille flow, how would you go about using linearity to prove that the

Blizzard [7]

Answer Explanation :

Poiseuille equation: this equation is used for non ideal flow this is used for the calculation of pressure in laminar flow it is physical law we know that fluid in laminar flow, flows across the pipe whose diameter is larger than the length of pipe

in mathematical form the equation can be expressed as

Q = $\frac{(P_2-P_1) r^{4}\times \pi}{8\times\eta \times l }$

where η is the cofficient of viscosity

now if we assume a small sphere of radius a is suspended freely in the plane of the laminar flow then for assuring that the sphere does not migrate with the flow we have to calculate the rate of flow of the liquid

8 0

3 years ago

8. A 2 kg flower pot weighing 20 N falls from a window ledge.

Alina [70]

The force of the air resistance is 4 N.

The given parameters;

mass of the flower pot, m = 2 kg

weight of the flower pot, W = 20 N

Let the air resistance = F

Apply Newton's second law of motion to determine the force of the air resistance acting upward to oppose the motion of the pot falling downwards.

$\Sigma F = ma\\\\W - F = ma\\\\a = \frac{W - F}{m} \\\\8 = \frac{20 - F}{2} \\\\20 - F = 16\\\\F = 20 - 16\\\\F = 4 \ N$

Thus, the force of the air resistance is 4 N.

Learn more here: brainly.com/question/19887955

8 0

3 years ago

HURRY URGENT ASAP I WILL GIVE BRAINLIEST

Leto [7]

Answer:

Explanation:

4 0

3 years ago

The weight of spaceman Speff at the surface of planet X, solely due to its gravitational pull, is 389 N. If he moves to a distan

miv72 [106K]

Answer:

mass of the planet X = 5.6 × 10²³ kg.

Explanation:

According to Newtons law of universal gravitation,

F = GM₁M₂/r²

Where F = gravitational force, M₁ = mass of the speff, M₂ = mass of the planet X, G = gravitational constant r = distance between the speff and the planet X

making M₂ The subject of the equation above,

M₂ = Fr²/GM₁ .......................... equation 2

Where F = 24.31 N, r = 1.08×18⁴km ⇒( convert to m ) =1.08 × 10⁴ × 1000 m

r = 1.08 × 10⁷ m, G = 6.67 × 10 ⁻¹¹ Nm²/kg², M₁ = 75 kg

Substituting this values in equation 2,

M₂ = 24.13(1.08 × 10⁷ )²/75( 6.67 × 10 ⁻¹¹)

M₂ = 24.13 × 1.17 × 10¹⁴/500.25 × 10⁻¹¹

M₂ = (28.23 × 10¹⁴)/(500.25 × 10⁻¹¹)

M₂ = 0.056 × 10²⁵

M₂ = 5.6 × 10²³ kg.

Therefore mass of the planet X = 5.6 × 10²³ kg.

8 0

3 years ago