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3 years ago

Two identical waves are destructively interfere. What will happen to the resulting wave?

Physics

1 answer:

storchak [24]3 years ago

8 0

Answer:

Because the disturbances are in opposite directions for this superposition, the resulting amplitude is zero for pure destructive interference

Explanation:

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Very short pulses of high-intensity laser beams are used to repair detached portions of the retina of the eye. The brief pulses

Tom [10]

Answer:

a) U = 0.375 mJ

b) p_rad = 4.08 mPa

c) λ_med = 604 nm ; f_med = 3.7 * 10^14 Hz

d) E_o = 3.04 * 10^4 V / m , B _o = 1.013 *10^-4 Nm/Amp

Explanation:

Given:

λ_air : wavelength = 810 * 10^(-9) m

P: Power delivered = 0.25 W

d : Diameter of circular spot = 0.00051 m

c : speed of light vacuum = 3 * 10^8 m/s

n_air : refraction Index of light in air = 1

n_med : refraction Index of light in medium = 1.34

ε_o : permittivity of free space = 8.85 * 10^-12 C / Vm

part a

The Energy delivered to retina per pulse given that laser pulses are 1.50 ms long:

U = P*t

U = (0.25 ) * (0.0015 )

U = 0.375 mJ

Answer : U = 0.375 mJ

part b

What average pressure would the pulse of the laser beam exert at normal incidence on a surface in air if the beam is fully absorbed?

p_rad = I / c

Where I : Intensity = P / A

p_rad = P / A*c

Where A : Area of circular spot = pi*d^2 / 4

p_rad = 4P / pi*d^2*c

p_rad = 4(0.25) / pi*0.00051^2*(3.0 * 10^8)

p_rad = 0.00408 Pa

Answer : p_rad = 4.08 mPa

part c

What are the wavelength and frequency of the laser light inside the vitreous humor of the eye?

λ_med = n_air*λ_air / n_med

λ_med = (1) * (810 nm) / 1.34

λ_med = 604 nm

f_med = f_air

f_med = c / λ_air

f_med = (3*10^8) / (810 * 10^-9)

f_med = 3.7 * 10^14 Hz

Answer : λ_med = 604 nm ; f_med = 3.7 * 10^14 Hz

What is the electric and magnetic field amplitude in the laser beam?

I = P / A

I = 0.5*ε_o*c*E_o ^2

I = 4P / pi*d^2

Hence, E_o = ( 8 P / ε_o*c*pi*d^2 ) ^ 0.5

E_o = ( 8 * 0.25 / (8.85*10^-12) * (3*10^8) * π * (0.00051)^2) ^ 0.5

E_o = 3.04 * 10^4 V / m

For maximum magnetic field strength:

B_o = E_o / c

B_o = 3.04 * 10^4 / (3*10^8)

B _o = 1.013 *10^-4 Nm/Amp

Answer: E_o = 3.04 * 10^4 V / m , B _o = 1.013 *10^-4 Nm/Amp

5 0

3 years ago

2nd grade work. Anyone?

Temka [501]

Answer:

A. shadow

Explanation:

5 0

3 years ago

Read 2 more answers

The lens-makers’ equation applies to a lens immersed in a liquid if n in the equation is replaced by n2/n1. Here n2 refers to th

pickupchik [31]

Answer:

The focal length of the lens in water is $f_{water} = 262.68 cm$

The focal length of the mirror in water is $f =79.0cm$

Explanation:

From the question we are told that

The index of refraction of the lens material = $n_2$

The index of refraction of the medium surrounding the lens = $n_1$

The lens maker's formula is mathematically represented as

$\frac{1}{f} = (n -1) [\frac{1}{R_1} - \frac{1}{R_2} ]$

Where $f$ is the focal length

$n$ is the index of refraction

$R_1 and R_2$ are the radius of curvature of sphere 1 and 2 of the lens

From the question When the lens in air we have

$\frac{1}{f_{air}} = (n-1) [\frac{1}{R_1} - \frac{1}{R_2} ]$

When immersed in liquid the formula becomes

$\frac{1}{f_{water}} = [\frac{n_2}{n_1} - 1 ] [\frac{1}{R_1} - \frac{1}{R_2} ]$

The ratio of the focal length of the the two medium is mathematically evaluated as

$\frac{f_water}{f_{air}} = \frac{n_2 -1}{[\frac{n_2}{n_1} - 1] }$

From the question

$f_{air }$ = 79.0 cm

$n_2 = 1.55$

and the refractive index of water(material surrounding the lens) has a constant value of $n_1 = 1.33$

$\frac{f_{water}}{79} = \frac{1.55- 1}{\frac{1.55}{1.44} -1}$

$f_{water} = 262.68 cm$

The focal length of a mirror is dependent on the concept of reflection which is not affected by medium around it.

7 0

3 years ago

A golfer strikes a 0.059-kg golf ball with a force of 290 N. If the ball moves with a velocity of 69 m/s,

Ymorist [56]

Answer:

0.014s

Explanation:

Given parameters:

mass of golf ball = 0.059kg

force applied = 290N

velocity = 69m/s

initial velocity = 0m/s

Unknown:

Time of contact = ?

Solution;

We know that momentum is the quantity of motion of body possess;

Momentum = mass x velocity

Momentum = 0.059 x 69 = 4.1kgm/s

Also; impulse is the effect of the force acting on a body;

impulse = force x time = momentum

So;

Force x time = momentum

Time = $\frac{momentum}{force }$ = $\frac{4.1}{290}$ = 0.014s

4 0

3 years ago

Suppose that the Millennium Falcon orbits the Death Star 20,000m above the Star’s surface. Calculate the circular orbit velocity

Nataly [62]

Answer:

18.4 m/s

Explanation:

The gravitational force between the Death Star and the Millenium Falcon is equal to the centripetal force that keeps the Millenium Falcon in circular orbit:

$G\frac{Mm}{(R+h)^2}=m\frac{v^2}{R+h}$

where

$G=6.67\cdot 10^{-11} m^3 kg^{-1} s^{-2}$ is the gravitational constant

$M=5.1\cdot 10^{17} kg$ is the mass of the planet

$m=1.36\cdot 10^6 kg$ is the mass of the Millennium Falcon

$v$ is the orbital velocity of the Millennium Falcon

$R=\frac{160,000 m}{2}=80,000 m$ is the radius of the Death Star

$h=20,000 m$ is the altitude of the Millennium Falcon above the planet's surface

Solving the equation for v, we find the orbital velocity:

$v=\sqrt{\frac{GM}{R+h}}=\sqrt{\frac{(6.67\cdot 10^{-11})(5.1\cdot 10^{17} kg)}{80,000 m+20,000 m}}=18.4 m/s$

5 0

3 years ago