Which wave must have a medium to travel?

The wavelength of red helium-neon laser light in air is 632.8 nm.(a) What is its frequency? Hz(b) What is its wavelength in glas

vekshin1

<h2>Answers:</h2>

The speed of a wave is given by:

$v=f.\lambda$ (1)

Where $f$ is the frequency and $\lambda$ the wavelength.

In the case of light, its speed is:

$c=f.\lambda$ (2)

On the other hand, the described situation is known as Refraction, a phenomenon in which the light changes its direction when passing through a medium with a refractive index different from the other medium.

In this context, the Refractive index $n$ is a number that describes how fast light propagates through a medium or material, and is defined as the relation between the speed of light in vacuum ( $c=3(10)^{8}m/s$ ) and the speed of light $v$ in the second medium:

$n=\frac{c}{v}$ (3)

In addition, as the light changes its direction, its wavelength changes as well:

$n=\frac{\lambda_{air}}{\lambda_{glass}}$ (4)

Knowing this, let's begin with the answers:

<h2>a) Frequency</h2>

From equation (2) we can find $f$ :

$f=\frac{c}{\lambda}$ (5)

Knowing that $1nm=(10)^{-9}m$ :

$f=\frac{3(10)^{8}m/s}{632.8(10)^{-9}m}$

$f=4.74(10)^{14}Hz}$ (6) >>>Frequency of the helium-neon laser light

<h2>b) Wavelength in glass</h2>

We already know the wavelength of the light in air $\lambda_{air}$ and the index of refraction of the glass.

So, we only have to find the wavelength in glass $\lambda_{glass}$ from equation (4):

$\lambda_{glass}=\frac{\lambda_{air}}{n}$

$\lambda_{glass}=\frac{632.8(10)^{-9}m}{1.48}$

$\lambda_{glass}=427(10)^{-9}m=427nm$ (7) >>>Wavelength of the helium-neon laser light in glass

<h2>c) Speed in glass</h2>

From equation (3) we can find the speed $v$ of this light in glass:

$v=\frac{c}{n}$

$v=\frac{3(10)^{8}m/s}{1.48}$

$v=2.027(10)^{8}m/s$ (8) >>>Speed of the helium-neon laser light in glass

7 0

3 years ago

If 40.0 kj of energy are absorbed by .500 kg of water 10 degrees c, what is the final temperature of the water?

anastassius [24]

To solve the problem, we must use the following equation:

$Q=mC_s (T_f -T_i)$

where

Q is the amount of heat energy absorbed by the water

m is the mass of the water

Ti and Tf are the initial and final temperature

Cs is the specific heat capacity of the water

The data we have in this problem are:

Q=40.0 kJ

$C_s =4.186 kJ/kg^{\circ}C$

$T_i=10^{\circ}C$

m=0.500 kg

Substituting the data into the equation and re-arranging it, we find

$T_f = T_i + \frac{Q}{mC_s}=10^{\circ}+\frac{40.0 kJ}{(0.500 kg)(4.186 kJ/kg^{\circ}}=29.1^{\circ}C$

So the final temperature of the water will be 29.1 degrees.

8 0

3 years ago

A student uses a meter to measure 120 coulombs flowing through a circuit in 60 seconds. what is the current in this circuit?

Keith_Richards [23]

A student uses a meter to measure 120 coulombs flowing through a circuit in 60 seconds. The electric current in this circuit will be 2 A

Current is a flow of electrical charge carriers, usually electrons or electron-deficient atoms. The common symbol for current is the uppercase letter I. The standard unit is the ampere, symbolized by A.

current = charge / time

given

time = 60 seconds

charge = 120 Coulombs

current = Q / T = 120 / 60 = 2 A

To learn more about electric current here

brainly.com/question/12791045

#SPJ4

3 0

2 years ago

Nicholas sends 20.0 minutes ironing shirts with his 1800-watt irn . How many joules of energy were usedby the iron

Nuetrik [128]

1 watt = 1 joule/sec
1800 watts = 1800 joules/sec

   (1800 J/sec) x (20 min) x (60 sec/min)

   = (1800 x 20 x 60) joules = 2,160,000 joules .

   ( 2.16 megajoules )

6 0

4 years ago

Give an example of something moving that is not accelerating

Anastaziya [24]

Anything that doesnt have a change in magnitude or direction is something thats not accelerating. so, for example, a car moving at a constant speed of 5mph on a flat road is an example of an object moving but not accelerating

6 0

3 years ago