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
GREYUIT [131]
3 years ago
5

What is the intensity in W/m2 of a laser beam used to burn away cancerous tissue that, when 85.0% absorbed, puts 470 J of energy

into a circular spot 2.60 mm in diameter in 4.00 s?
Physics
1 answer:
Advocard [28]3 years ago
8 0

Answer:

26036485.6433 W/m²

Explanation:

E= Energy = 470 J

t = Time = 4 seconds

d = Diameter = 2.6 mm

Power is given by

P=\dfrac{E}{t}

Intensity is given by

I=\dfrac{P}{\pi r^2}\\\Rightarrow 0.85I=\dfrac{E}{t\dfrac{\pi}{4} d^2}\\\Rightarrow I=\dfrac{470}{0.85\times 4\times \dfrac{\pi}{4}\times (2.6\times 10^{-3})^2}\\\Rightarrow I=26036485.6433\ W/m^2

The intensity of the laser beam is 26036485.6433 W/m²

You might be interested in
A high-diver of mass 59.8 kg jumps off a board 10.0 m above the water. If, 1.00 s after entering the water his downward motion i
irinina [24]

la respuesta correcta es la "E"

6 0
2 years ago
Circuit A in a house has a voltage of 208 V and is limited by a 40.0-A circuit breaker. Circuit B is at 120.0 V and has a 20.0-A
Setler79 [48]

Given Information:  

Voltage of circuit A = Va = 208 Volts

Current of circuit A = Ia = 40 Amps

Voltage of circuit B = Vb = 120 Volts

Current of circuit B = Ib = 20 Amps

Required Information:  

Ratio of power = Pa/Pb = ?

Answer:  

Ratio of power = Pa/Pb = 52/15

Explanation:  

Power can be calculated using Ohm's law

P = VI

Where V is the voltage and I is the current flowing in the circuit.

The power delivered by circuit A is

Pa = Va*Ia

Pa = 208*40

Pa = 8320 Watts

The power delivered by circuit B is

Pb = Vb*Ib

Pb = 120*20

Pb = 2400 Watts

Therefore, the ratio of the maximum power delivered by circuit A to that delivered by circuit B is

Pa/Pb = 8320/2400

Pa/Pb = 52/15

4 0
3 years ago
Discuss the phase change condition due to reflection of light from a surface. Summarize equations of interference for thin film.
Dmitrij [34]

Answer:

if this surface has a higher index than in the medium where the light travels, the reflected wave has a phase change of 180º

Explanation:

When a ray of light falls on a surface if this surface has a higher index than in the medium where the light travels, the reflected wave has a phase change of 180º this can be explained by Newton's third law, the light when arriving pushes the atoms of the medium that is more dense, and these atoms respond with a force of equal magnitude, but in the opposite direction.

When the fractional index is lower than that of the medium where the reflacted beam travels, notice a change in phase.

Also, when light penetrates the medium, it modifies its wavelength

              λ = λ₀ / n

We take these two aspects into account, the condition for contributory interference is

            d sin θ = (m + 1/2) λ

for destructive interference we have

            d sin θ = m λ

in general this phenomenon is observed at 90º

           2 d = (m +1/2) λ° / n

          2nd = (m + ½) λ₀

5 0
3 years ago
Topographic maps represent an area's physical features by describing _____.
jasenka [17]
B is the answer.....
5 0
2 years ago
Read 2 more answers
An egg is thrown upward with a velocity of 4.5 m/s. How long will it take to reach it's maximum height?
Ray Of Light [21]

Answer:

0.45 seconds

Explanation:

Letting the value of g = 10 m/s/s

final velocity (v) = 0 m/s (since the egg will come to rest at the maximum height)

initial velocity(u) = 4.5 m/s

acceleration = -10 m/s/s (since the gravity is acting against the egg)

time = t seconds

From the first equation of motion:

<em>v = u + at</em>

<em>0 = 4.5 + (-10)t</em>

<em>t = -4.5 / -10</em>

t = 0.45 seconds

3 0
3 years ago
Other questions:
  • What particle flows to produce electric current
    8·1 answer
  • Explain how a volcanologist can piece together the history of a volcano by studying the rock that makes up the volcano
    10·1 answer
  • Uma garota de 50 kg esta sobre um skate de 10kg,ambos movendo se em sentido horizontal, da esquerda para a direita, a velocidade
    12·1 answer
  • PLS URGENT!!
    15·1 answer
  • What most closley defines population density?
    13·1 answer
  • About how long does it take Earth to complete one revolution around the Sun?
    14·2 answers
  • #38 , what is this answer?
    10·2 answers
  • Light my fire! Mix me with cerium and we’ll make beautiful mischmetal together!
    12·2 answers
  • Kindly answer the question about Work and Power. Image is attached below.
    5·1 answer
  • A van of mass 5,000kg travelling at a velocity of 10 m/s collides with a stationary car. The vehicles move together after the im
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!