Problem 3 (a) Assuming the human body (skin temperature 34◦C) to behave like an ideal thermal radiator, find the wavelength where the intensity from the body is a maximum. In what region of the electromagnetic spectrum is radiation with this wavelength? (b) Making whatever (reasonable) assumptions you may need, estimate the power radiated by a typical person isolated from the surroundings. (c) Estimate the radiation power absorbed by a person in a room in which the temperature is 20◦C.

Answers

Answer 1

Answer:

Explanation:

a )

We shall apply Wein's displacement law

λm x T = b where λm is wavelength of radiation having maximum intensity

T is absolute temperature of body , and b is  a constant

b = 2898 μm-K

T = 273 + 34 = 307 K

λm x 307 = 2898

λm = 9.44 μm

= 9440 nm

It is infrared radiation .

b )

We shall apply Stefan's law of radiation.

E = σA T⁴

E is emitted radiation by body acting as black body   , A is surface area , T is absolute temperature of body

σ = 5.67 x 10⁻⁸ J / m²T⁴

Surface area of a typical man's body A = 1.9 m²

T = 273 + 34 = 307 K

Assuming human body as black body

E = 5.67 x 10⁻⁸ x 1.9 x 307⁴ J/s

= 9.57 x 10² J/s

= 957 W .

c )

Radiation absorbed

E = 5.67 x 10⁻⁸ x 1.9 x ( 273 + 20 )⁴ J/s

= 794 W .


Related Questions

ELE Review questions
POSSIBLE POINTS: 3
Match the energy transformation sequence with the device it describes:
A hair dryer plugged into the wall
a
A hand crank generator emergency radio
A battery operated fan
11 CE to ELE
+ ELE to KE
:: KE to ELE
h
1
2
A Review

Answers

Answer:

1. ELE to KE = Electrical energy conversion to kinetic energy.

2. KE to ELE = kinetic energy conversion to electrical energy.

3. CE to ELE = chemical energy conversion to electrical energy.

Explanation:

The Law of Conservation of Energy states that energy cannot be destroyed but can only be transformed or converted from one form to another.

Some examples of energy are chemical energy, electrical energy, kinetic energy, sound energy, potential energy, light energy, etc.

The transformation of energy from one form to another are described below;

1. A hair dryer plugged into the wall: it involves the conversion of electrical energy to kinetic energy. The energy type present in the wall socket is electrical energy which powers the hair dryer to have kinetic energy i.e the energy possessed due to motion of hair dryer.

2. A hand crank generator emergency radio: it illustrates the conversion of kinetic energy to electrical energy. The hand crank generator possess kinetic energy as it is being wounded before it is then converted into electrical energy which powers the radio.

3. A battery operated fan: it illustrates the conversion of chemical energy to electrical energy. The cells present in battery possess chemical energy that is being converted into electrical energy to power the fan.

A3 kg mass takes some impulse in order increase its velocity from 11
m/s to 25 m/s. Calculate the impulse it took.

Answers

Answer:

JAKSJAKZNPWLAQJZOAKZONZPW

THE ANSWER IS FAILURE

what scale ranks minerals from softest to hardest

Answers

Answer: Mohs Scale

Explanation: Mohs Scale of Hardness

hope this helped!!!!!!!!!!!

When potassium chromate (K2CrO4) is added to a solution containing 0.500 g silver nitrate (AgNO3), solid silver chromate (Ag2CrO4) is formed. a) Determine the chromate precipitate

Answers

Answer:

OK id k the names of everything but the quantity would be around 2.22222222222222222222222222222222222222222222222222222222222222222222222222222 ok?

Explanation:

image.
A concave lens always produces a(n)
A. inverted
o
B. real
C. virtual
D. magnified

Answers

Answer : B - real

Explanation : 1. you can see the image the way it is as in its no in a mirror.
2. The image will not be inverted

But it could be magnified too tbh. But I would go for real

Answer:

Explanation:

Its Virtual, how would you describe the image formed by a convex mirrior? virtual upright, smaller

Can heating cooking oil you’ll be classified as producing a chemical change?

Answers

yes it is boiling creating bubbles that aren't their originally

Explanation:

When cooking oils are subjected to heat in the presence of air and water (from food), such as in deep-fat frying and sautéing (pan frying), they can undergo at least three chemical changes: 1) oxidation of the fatty acids, 2) polymerization of the fatty acids, and 3) breaking apart of the triglyceride molecules into free fatty acids and glycerol by hydrolysis (reaction with water from the food being cooked) (Choe and Min 2007)

Which diagram is the best model for a solid?
Substance A
Substance B
О Substance C

Answers

Answer:

This link was diagram

Explanation:

https://doubtnut.app.link/FnsNC80Dccb

- What is the mass of a bowling ball that weights 80 Newtons on Earth?
(17 Points)
8 kg
80 kg
800 kg

Answers

I’d say it’s 8 or 80
Hopefully this helps sorry

Answer:

800 kg

Explanation:

how do newton's 3 laws of motion effective everyday life?

Answers

Answer:

Examples of Newton's third law of motion are ubiquitous in everyday life. For example, when you jump, your legs apply a force to the ground, and the ground applies and equal and opposite reaction force that propels you into the air. Engineers apply Newton's third law when designing rockets and other projectile devices.

Explanation:


Need help guys please

Answers

Answer:

c is the answer,................

Explain why stones are strong in compression but weak in tension ​

Answers

Answer:

Gigantic towers, monuments and tall structures are always supported by a very thick layer of concrete that’s blended into their foundation. The purpose of this is quite straightforward: nothing provides greater support to a super heavy (and stationary) structure than a layer of concrete.  There may be other things that, in theory, could provide a stronger foundation, but they wouldn’t be nearly as cost effective as concrete.

Answer:

Because it has essentially zero strength in tension, it is almost always used as reinforced concrete, a composite material. It is a mixture of sand, aggregate, cement and water.

Newton's first Law implies that an object at rest will remain at rest unlss a net force acts on it / TRUE or FALSE?

Answers

Answer:

True

Explanation:

If an object is at rest it will stay at rest unless a force acts on it.

Atoms of which pair of elements will form ionic bonds in a compound?

A.
Ti and Ni
B.
Ti and O
C.
Cl and Br
D.
P and Cl

Answers

Answer:

Ti and O

Explanation:

It is what it is.

Answer:

B. Ti and O

Explanation:

A.P.E.X

Define :density٬archimedes principle

Answers

Answer:

density is defined as the amount of mass contained in unit volume of a body .its si unit is kg/m*3

Answer:

Density is the amount of mass per unit volume of a substance.

Archimedes principle states that"When a body is totally or partially immersed in a liquid,it experience an upthrust which is equal to the weight of the liquid displaced"

give two differences between sextusl reproduction and asextual reproduction

Answers

Answer:

Sexual reproduction you need two organisms to reproduce.

Asexual is when you can multiply yourself and there is nothing different about the offspring and the parent.

Consider this situation: A baseball player dives head-first
into second base and slows down while sliding on the infield
dirt. Of the forces listed, identify which act upon the player.

Answers

Of the forces listed I think the force of him diving and sliding across the infield acted on the player.

I think so because the slowing down was a result of an action, and I don’t think that should count as An action when it is the result of an action. However, the act of diving head-first into second base and sliding across the infield are independent actions and will cause friction, which will act upon the player.

how was newton's laws used to solve problems on apollo 13 ship
Explain in two full paragraphs

Answers

Answer:

actually ships are made in newtons third law of motion.it states to every action there is equal and opposite reaction. curved is made in downwards to maintain upthrust and to made balance.

actually it prevents ships from drowning and to move with a heavy mass.

Determine the position of a train moving at 45 m/s after 5 minutes.

Answers

The train has covered 13,500 meters of track.

We don't know its position, because we don't know where it started from, and we don't know how straight the track is.

Describe 2 characteristics of the spring tide. *

Answers

Answer:

Spring tide, tide of maximal range, near the time of new and full moon when the Sun and Moon are in syzygy—i.e., aligned with the Earth. ... In either case of syzygy, the tide-producing forces of the Sun and the Moon reinforce each other, and the tidal amplitudes on Earth are at their greatest.

8.
Billiard ball A, mass 0.17 kg, is moving due east with a velocity of 4.0
m/s. It strikes stationary billiard ball B, which has the same mass. After
the collision, ball A moves at an angle of 30° north of east with a
velocity of 3.5 m/s. Ball B moves at an angle of 60° south of east.
What is the speed of ball B?

Answers

Answer:

2 m/s

Explanation:

The momentum of the colliding system is conserved . Therefore, the velocity of the ball B with the same mass as A is 0.52 m/s.

What is momentum ?

Momentum of a body is the ability to bring the applied force makes maximum displacement. it is the product of mass and velocity. For a collision, the sum of initial momentum of the two bodies is equal to the sum of their final momentum.

Thus, u be the initial velocity and v be the final velocity.

Then, m1 u1+ m2 u2 = m1 v1 + m1 v2

m1 =  0.17 kg

u1 = 4 m/s

m2 = 0.17 kg

u2 = 0

Then initial momentum = 0.17 × 4 m/s + 0 = 0.68 kg m/s

v1 = 3.5 m/s

0.68 kg m/s = (0.17 × 3.5 m/s ) +  (0.17 × v2)

then v2 = 0.52 m/s.

Therefore, the velocity of ball B after collision will be 0.52 m/s.

Find more on momentum:

https://brainly.com/question/24030570

#SPJ2

1) A spring, which has a spring constant k=7.50 N/m, has been stretched 0.40 m from ts equilibrium position . What the potential energy now tored in the spring ?

Answers

Answer:

[tex]\displaystyle U_s = 0.6 \ J[/tex]

General Formulas and Concepts:

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Physics

Energy

Elastic Potential Energy: [tex]\displaystyle U_s = \frac{1}{2} k \triangle x^2[/tex]

U is energy (in J)k is spring constant (in N/m)Δx is displacement from equilibrium (in m)Explanation:

Step 1: Define

k  = 7.50 N/m

Δx = 0.40 m

Step 2: Find Potential Energy

Substitute in variables [Elastic Potential Energy]:                                        [tex]\displaystyle U_s = \frac{1}{2} (7.50 \ N/m) (0.40 \ m)^2[/tex]Evaluate exponents:                                                                                      [tex]\displaystyle U_s = \frac{1}{2} (7.50 \ N/m) (0.16 \ m^2)[/tex]Multiply:                                                                                                           [tex]\displaystyle U_s = (3.75 \ N/m) (0.16 \ m^2)[/tex]Multiply:                                                                                                           [tex]\displaystyle U_s = 0.6 \ J[/tex]

Question 11 (1 point)

Anytime there is height, the object must have...

a

kinetic energy

gravitational potential energy

GPE & KPE

C

Od

elastic potential energy

Answers

Answer:

gravitational potential energy.

Explanation:

Gravitational potential energy (GPE) can be defined as an energy possessed by an object or body due to its position above the earth surface.

Mathematically, gravitational potential energy is given by the formula;

[tex] G.P.E = mgh[/tex]

Where,

G.P.E represents gravitational potential energy measured in Joules.

m represents the mass of an object.

g represents acceleration due to gravity measured in meters per seconds square.

h represents the height measured in meters.

This ultimately implies that, anytime there is height, the object must have gravitational potential energy.

Hence, an object possesses gravitational potential energy due to its height (position) and the earth's gravitational force.

Which is the MOST likely reason scientists are trying to find ways to get energy from more renewable
resources?
А
Renewable resources cost less to produce than
energy from nonrenewable resources
B
Renewable resources are easier to replace than
nonrenewable resources
C
Renewable resources create more power than
nonrenewable resources
D
Renewable resources put more pollution in the air than nonrenewable resources

Answers

The correct answer is A “renewable resources cost less to produce than energy from non renewable resources

What provides most of the force to allow the runners to move?

Answers

Answer:

When you are running the most important force that you should understand is friction. Friction is a force that opposes movement between two objects, but for runners friction makes you faster. Friction gives you a better and more efficient way to use your energy into speed.

The reaction force provided by the tracks as the runners press their feet against the track provides the maximum force.

What is newtons third law of motion?

The newton's third law of motion states that every action has a equal and opposite reaction

Given is to find what force allow the runners to move.

The reaction force provided by the tracks just before the runners start running as they press their feet against the track provides the maximum force.

Therefore, the reaction force provided by the tracks as the runners press their feet against the track provides the maximum force.

To solve more questions on force, visit the link below -

https://brainly.com/question/3952884

#SPJ6

7. An electric kettle is connected to a mains voltage of 230 V. The current in the kettle is 12 A. Calculate the power of the kettle

Answers

Answer:

2,760watts

Explanation:

Power of the kettle = current * voltage

P = IV

Given

I = 12A

V = 230V

Substitute into the formula

Power of the kettle = 12*230

Power of the kettle = 2,760watts

(b) The efficiency of the pump which operates the fountain is 70%.
Calculate the power supplied to the pump.​

Answers

Answer:

Power supplied to the pump is 980000 W or 980 KW

Note: The question is incomplete. The complete question is given below:

On a day with no wind, a fountain in Switzerland propels 30000 kg of water per minute to a height of 140 metres.

a)Calculate the power used in raising the water?

b)The efficiency of the pump which operates the fountain is 70%

calculate the power supplied to the pump?

Explanation:

Efficiency = Power output/Power input * 100%

Power output = work done/ time

where work done = mass * acceleration due to gravity (g) * height

time = 1 minute = 60 seconds

mass of water = 30000 kg, height = 140 meters, g = 9.8 m/s²

Then, work done = 30000 * 140 * 9.8 = 41160000 J

Power output then = 41160000 J / 60 s

Power output = 686000 W

The power input can then be derived from the formula of efficiency

Power input = (Power output * 100)/Efficiency

Power input = (100 * 686000) / 70

Power input = 980000 W

Therefore, power supplied to the pump is 980000 W or 980 KW

A 2.70 kg book rests on an incline of 13.0. You give it a sharp push up the frictionless ramp. It comes to a stop in 25.25 at 17.5 m up the ramp before starting its descent(a) What is the magnitude of the normal force on the book

Answers

Answer:

the magnitude of the normal force on the book is 25.78N

Explanation:

The computation of the magnitude of the normal force on the book is shown below

Normal force = N is

= mgcosβ

= 2.70 × 9.8 × cos13°

= 25.78N

hence, the magnitude of the normal force on the book is 25.78N

The above formula should be applied

Three point charges are fixed in place in a right triangle, as shown in the figure.
What is the magnitude of the electric force on the +1.00-C charge due to the other two charges?
What angle does the force make with the -x-axis? A positive angle is counterclockwise from the -x-axis.

Answers

For the three-point charges fixed in a right triangle, we have:

1. The magnitude of the electric force on the +1.00 μC charge is 1.79 N.

2. The force does an angle of 21.68° with the x-axis.

1. Magnitude of the electric force

First, let's denote the charges as is shown in the picture below:

q₁: is the charge 1 = +0.800 μC = +0.800x10⁻⁶ Cq₂: is the charge 2 = +1.00 μC = +1.00x10⁻⁶ Cq₃: is the charge 3 = -0.600 μC = -0.600x10⁻⁶ C

                                                                       

The magnitude of the electric force on the charge 2 (+1.00 μC) is given by:  

[tex]|F_{net}| = \sqrt{(\Sigma\vec{F}_{x})^{2} + (\Sigma\vec{F}_{y})^{2}}[/tex]  (1)    

Where:  

[tex]\Sigma\vec{F}_{x}[/tex]: is the sum of the forces acting on the x-axis[tex]\Sigma\vec{F}_{y}[/tex]: is the sum of the forces acting on the y-axis

We can calculate the electrical forces with Coulomb's law:

[tex]\vec{F} = \frac{Kq_{1}q_{2}}{d^{2}}[/tex]

Where:

K is the Coulomb's constant = 9.00x10⁹ Nm²/C²  q₁ and q₂ are the chargesd is the distance between the charges

     

Forces in the x-axis ([tex]\Sigma\vec{F}_{x}[/tex])

The forces in the x-component are given by:

[tex]\Sigma\vec{F}_{x} = \vec{F}_{21}_{x} + \vec{F}_{23}_{x}[/tex]

[tex]\Sigma\vec{F}_{x} = \vec{F}_{21}_{x}cos(\theta) + \vec{F}_{23}_{x}[/tex]

[tex]\Sigma\vec{F}_{x} = \frac{Kq_{1}q_{2}}{d_{12}^{2}}cos(\theta) + \frac{Kq_{2}q_{3}}{d_{23}^{2}}[/tex]   (2)

Where:              

θ: is the angle of the force F₂₁ with the x-axisd₁₂ = z = 9.60 cm = 0.0960 m  d₂₃ = x

We can calculate the angle θ with the following trigonometric function:

[tex]sin(\theta) = \frac{y}{z}[/tex]

[tex]\theta = sin^{-1}(\frac{y}{z}) = sin^{-1}(\frac{8.10 cm}{9.60 cm}) = 57.5 ^\circ[/tex]

To find the distance x (d₂₃), we need to use Pythagoras:

[tex]x = \sqrt{z^{2} - y^{2}} = \sqrt{(0.0960 m)^{2} - (0.0810 m)^{2}} = 0.051 m[/tex]

 

After entering θ and x (d₂₃) into equation 2, we have:

[tex]\Sigma\vec{F}_{x} = \frac{9.00\cdot 10^{9} Nm^{2}C^{-2}(0.800 \cdot 10^{-6} C)(1.00 \cdot 10^{-6} C)}{(0.0960 m)^{2}}cos(57.5) + \frac{9.00 \cdot 10^{9}Nm^{2}C^{-2}(1.00 \cdot 10^{-6} C)(-0.600 \cdot 10^{-6} C)}{(0.051 m)^{2}}[/tex]

[tex]\Sigma\vec{F}_{x} = [0.78*cos(57.5) + (-2.08) N] = -1.66 N[/tex]

Hence, the x-component of the force is -1.66 N.

Forces in the y-axis ([tex]\Sigma\vec{F}_{y}[/tex])

The only force acting on the y-axis is the y-component of the force F₂₁, so:

[tex]\Sigma\vec{F}_{y} = -\vec{F}_{21}_{y} = -\vec{F}_{21}sin(\theta)[/tex]

The minus sign is because the vector is pointing in the negative y-direction (see the picture below).

[tex]\Sigma \vec{F}_{y} = -\frac{9.00\cdot 10^{9} Nm^{2}C^{-2}(0.800 \cdot 10^{-6} C)(1.00 \cdot 10^{-6} C)}{(0.0960 m)^{2}}sin(57.5) = -0.66 N[/tex]

Hence, the y-component of the force is -0.66 N.

Finally, the magnitude of the electric force on the charge +1.00 μC is (eq 1):  

[tex]|F_{net}| = \sqrt{(-1.66 N)^{2} + (-0.66 N)^{2}} = 1.79 N[/tex]                                  

Therefore, the magnitude of the electric force on the +1.00 μC charge is 1.79 N.

2. Direction of the force with the x-axis

According to the picture below, the angle of the force with respect to the x-axis is given by:  

[tex]tan(\beta) = \frac{\Sigma\vec{F}_{y}}{\Sigma\vec{F}_{x}}[/tex]

[tex]\beta = tan^{-1}(\frac{-0.66 N}{-1.66 N}) = 21.68 ^\circ[/tex]

Therefore, the force does an angle of 21.68° with the x-axis.

Find more about Coulomb's law here:  

brainly.com/question/506926        

I hope it helps you!                

1.
During parkour, a person leaps at a wall and performs a flip. What must they do to change
directions?
6

Answers

Answer:

they push off the wall with a force greater than the wall

Explanation:

The game of parkour involves moving from one point to another and performing several skills which includes flips, especially in a difficult environment.

To change directions, the person must exert a significant force on the wall.

When the person leaps on the wall, it means the person moves or jumps quickly on the wall.

While this is being carried out, the concept of force must be applied.

If the force that acts on a stationary object is smaller than the required force to move the object, the object's position remains unchanged.

This means that for the person's direction to change, the person must exact a great force (or a significant force) enough to cause a change in direction.

Read more about force at:

https://brainly.com/question/19734564

A light source emits light with dominant wavelengths in the range of 650 to 690 nm. what is the principle color of light emitted by the source?

Answers

Answer:

Please see below as the answer is self-explanatory.

Explanation:

The visible range extends roughly from 400 nm (violet) to 700 nm (red).Below the violet is the ultra-violet spectrum (with higher energy) and above red, we have the infra-red spectrum.The wavelengths in the range of 650 to 690 nm have red as the dominant color.
Other Questions
9 strings of lights for $52.65 .how much does one string of lights cost ? Write the following equation in slope-intercept form and then graph: 4x + 3y = 12 Matching list - biology learning task 4 answer the following show your solution using decimal and proportion methods 1. in survey the barangay had a certain number of families and 60% of them are identified and belong to the poor or marginalized sector if the total families is 150 how many families are belong to the poor sector? 2. lola remedios went to groceries to buy her daily needs if the total amount of her groceries is P 2,500.00 what would be the new amount if the store granted her 20% senior citizens discounts?3. a passenger bus can accommodate 60 sits. During pandemic they reduce their accommodation to 50%. what is the actual sits can accommodate by the passengers? What is the answer??? what is the total surface area of a cylinder with a base of 11m and a height of 7m What is the density of an object that has a mass of 54g and a volume of 9 mL Is it possible tha static leccy start a fire in me bed or not? Role of Ibn Sina in the field of medicine? While there are a few variations of the sign for Easter, what handshape do all of them use?A. BB. EC. an egg shapeD. AWhat is the answer? PLEASE HELP, WILL MARK BRAINLESTExamine the following image. Which ocean-floor feature is indicated by the arrow in the image?A diagram showing a location where seafloor spreading occursPublic Domain Guyot Mid-ocean ridge Seamount Trench Human impact on ecosystems will lead to secondary succession over primary succession true or false y = mx + b is a slope intercept form of a line. Rewrite the formula in terms of x. PLS HELP I WILL GIVE BRIANLY!!2/5 x 5/4 in fraction in its simplest form Please help will give Brain 50 POINTS! SHOW WORK OR ILL REPORT what is judicial review? * A The power to declare laws or executive orders unconstitutional.B The steps needed to appeal a case.C The power to review bills created by Congress before they are sent to the President.D The power to impeach a Supreme Court justice. I WILL GIVE BRAINLIESTThe first step that Juan performed to simplify the expression 3.6 + 0.4(3.8 5.9) 0.5 before entering it into the calculator is shown.4(3.8 5.9) 0.5Which statement is true?Juan performed the first step correctly.The first step should have been 3.6 + 0.4(2.1) 0.5.The first step should have been 3.6 + 0.4(2.1) 0.5.The first step should have been 3.6 + 1.52 5.9 0.5. 3. Which Founding Father wrote most of the Federalist Papers? Benjamin Franklin George Washington Alexander Hamilton John Jay 10 ft area = 170 ft