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3 years ago

The index of refraction for water is about 4 3 . What happens as a beam of light travels from air into water?

Physics

1 answer:

hjlf3 years ago

5 0

Answer:

Its speed decreases.

Explanation:

When light enters into water, its speed decreases (as well as its frequency). This is the reason why refraction (the bending of light when it changes media) occurs.

This can be proven mathematically.

Given that the refractive index of water is 4/3, we know that refractive index is the ratio of the speed of light in a vacuum to the speed of light in another medium.

Therefore,

4/3 = (speed of light in vacuum) / (speed of light in water)

Speed of light in a vacuum is 3 * 10^8. Hence,

Speed of light in water is:

v = (3 * 10^8) / (4/3)

v = 2.25 * 10^8 m/s

As we can see, the speed of light decreases in water.

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A centrifugal pump discharges 300 gpm against a head of 55 ft when the speed is 1500 rpm. The diameter of the impeller is 15.5 i

Ksivusya [100]

Answer: Question 1: Efficiency is 0.6944

Question 2: speed of similar pump is 2067rpm

Explanation:

Question 1:

Flow rate of pump 1 (Q1) = 300gpm

Flow rate of pump 2 (Q2) = 400gpm

Head of pump (H)= 55ft

Speed of pump1 (v1)= 1500rpm

Speed of pump2(v2) = ?

Diameter of impeller in pump 1= 15.5in = 0.3937m

Diameter of impeller in pump 2= 15in = 0.381

B.H.P= 6.0

Assuming cold water, S.G = 1.0

eff= (H x Q x S.G)/ 3960 x B.H.P

= (55x 300x 1)/3960x 6

= 0.6944

Question 2:

Q = A x V. (1)

A1 x v1 = A2 x V2. (2)

Since A1 = A2 = A ( since they are geometrically similar

A = Q1/V1 = Q2/V2. (3)

V1(m/s) = r x 2π x N(rpm)/60

= (0.3937x 2 x π x 1500)/2x 60

= 30.925m/s

Using equation (3)

V2 = (400 x 30.925)/300

= 41.2335m/s

To rpm:

N(rpm) = (60 x V(m/s))/2 x π x r

= (60 x 41.2335)/ 2× π × 0.1905

= 2067rpm.

6 0

3 years ago

Suppose you have a coffee mug with a circular cross section and vertical sides (uniform radius). What is its inside radius if it

Vlad [161]

Answer:

r = 4.62 cm

Explanation:

Mass of a coffee, m = 370 g

Height of the mug, h = 5.5 cm

We need to find the inside radius of the mug. Density of an object is equal to the mass per unit volume. It can be given by :

$d=\dfrac{m}{V}\\\\d=\dfrac{m}{\pi r^2 h}\\\\r=\sqrt{\dfrac{m}{\pi dh}}\\\\r=\sqrt{\dfrac{370\ g}{\pi \times 1\ g/cm^3\times 5.5\ cm}}\\\\r=4.62\ cm$

So, the inside radius is 4.62 cm.

8 0

3 years ago

Explain why is takes longer to hard boil an egg at high altitudes than at sea level.

krok68 [10]

Water boils at lower tempertature at higher altitude

3 0

3 years ago

Read 2 more answers

A bird lands on a bare copper wire carrying a current of 51

nirvana33 [79]

The resistance of the piece of wire is
$R= \frac{\rho L}{A}$
where
$\rho = 1.68 \cdot 10^{-8}\Omega m$ is the resistivity of the copper
$L=5.1 cm=0.051 m$ is the length of the piece of wire
$A=0.13 cm^2 = 0.13 \cdot 10^{-4} m^2$ is the cross sectional area of the wire
By substituting these values, we find the value of R:
$R= \frac{\rho L}{A}=6.6 \cdot 10^{-5} \Omega$

Then, by using Ohm's law, we find the potential difference between the two points of the wire:
$V=IR=(51 A)(6.6 \cdot 10^{-5} \Omega )=3.4 \cdot 10^{-3} V$

7 0

3 years ago

A constant force of 120 N pushes a 55 kg wagon across an 8 m level surface. If the wagon was initially at rest, what is the fina

Illusion [34]

Answer:

The kinetic energy of the wagon is 967.0 J

Explanation:

Given that,

Force = 120 N

Mass = 55 kg

Height = 8 m

We need to calculate the kinetic energy of the wagon