Which of the following expression is correct for radiation efficiency?
a) ηr=PrPl
b) ηr=PrPr−Pl
c) ηr=PrPr+Pl
d) ηr=PlPr+Pl

The child should be at a distance of [tex]13.8 * 10^{6} m[/tex] from center of earth.

We know that gravity at height h is given by , [tex]g = \frac{GM}{(r+h)^{2} }[/tex]

where, G = gravitational constant = [tex]6.67 * 10^{-11}[/tex]

           M = mass of earth = [tex]5.98 * 10^{24} kg\\[/tex]

            r = radius of earth = [tex]6.371 * 10^{6} m[/tex]

     let g = [tex]9.8 m/s^{2}[/tex]

           h = distance from center of earth

The value of g is inverse to the height above the earth’s surface; therefore, it decreases with increasing height.

Putting these values in above equation we get, h = [tex]13.8 * 10^{6} m[/tex]

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The particle's lifetime distance at rest is 1.2376 m.

Here, the particle's lifetime refers to the the distance in speed formula

Speed is the measure of average distance in a given time. It is the vector quantity.

The distance can be calculated by the product of speed and the time given.

Here, in this question, the total distance a certain elementary particle has traveled in its lifetime.

This can be determined by merely multiplying the speed with the lifetime of years.

Given,

Speed = 2.6×10⁸ m/s

Time = 4.76×10⁻⁶ s

Speed = distance / time

Distance = speed * time

Total distance = (2.6×10⁸ m/s)*(4.76×10⁻⁶ s)

Total distance = 1.2376 meters

Therefore, the distance travelled by the particle with the speed of 2.6×10⁸ m/s in the lifetime is 1.2376 m

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Every air conditioner has a preset temperature. If used continously, the temperature goes down the reset temperature and breaks down.

And then it would pump the heat out and a lot of energy would be released  

When the air conditioner is mounted inside a room, it only transfers heat within the room. The air conditioner does not change the form of the heat; it only absorbs the heat from inside the room and ejects it outside the room.

According to the second law of thermodynamics, in a closed system, the heat is increasing or remains constant. It never decreases.

So as the air conditioner cools the room, it has to pump the heat out from inside the room.

Every air conditioner has a preset temperature. If used continously, the temperature goes down the reset temperature and breaks down.

And then it would pump the heat out and a lot of energy would be released  

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a. 1.43 s long does it take her to reach a speed of 2.00 m/s.

b. −1.79m/s² is her deceleration.

Calculation :

a. We are given the initial velocity, u=0 m/s, the acceleration, a=1.4 m/s² and the final velocity, v=2.00 m/s. Therefore, we shall calculate the time taken to reach such a final velocity by applying the following equation of kinematics,

v=u+at [1]

=at

∴t=v/a   [Dividing both sides by the acceleration]

=[tex]\frac{2.00 m/s}{1.4 m/s^{2} }[/tex]

=1.42857 s

≈1.43 s

It takes her 1.43 s to reach a speed of 2.00 m/s.

b. From above, the initial velocity is now, u1=1.43 m/s and the final velocity, v1=0 m/s. Thus, the deceleration, a, is calculated using the same equation [1] as follows,

v=u+at

0=u+at

∴a=−ut=[tex]\frac{-1.43 m/s}{ 0.800 s}[/tex]

= −1.7875 m/s²

≈−1.79 m/s²

Therefore, the deceleration of the car is

1.79 m/s²

In mechanics, acceleration is the rate of change of an object's velocity with respect to time. Acceleration is a vector quantity (as long as it has magnitude and direction). The direction of an object's acceleration is given by the direction of the net force acting on that object. As described in Newton's second law, the magnitude of an object's acceleration is the combined effect of two sources.

The mass of this object is inversely proportional to the mass of the object, depending on the material from which it is made.

The SI unit of acceleration is meters per square second

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It is not a property of epithelial tissue that the basement membrane is lacking in the cells. The apical and basal surfaces of epithelial cells are distinct from one another in terms of both structure and function.

The configuration of epithelial cells, which fit tightly together to form unbroken sheets of cells, indicates that their function is to form linings or covering membranes.

There are many epithelial tissues in the human body. They make up the majority of the tissue in glands, line body cavities and hollow organs, and cover all of the body's surfaces. Among the several functions they perform are protection, secretion, absorption, excretion, filtration, diffusion, and sensory reception.

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The tension exerted on the bolt by the worker and the weight of the beam is 15023.4 Nm in size.

The parameters are as follows: length of steel, L = 4.20m; mass of steel, m = 580 kg; and mass of work, m = 75.0 kg.

The following formula is used to determine how much torque the worker's weight and the weight of the beam will exert on the bolt;

the beam's center of gravity [tex]\frac{4.20}{2} = 2.1 m[/tex]

[tex]T_{t}=T_{1}+T_{1}[/tex]

[tex]T_{t}=F_{1}.r_{1}+F_{2}.r_{2}[/tex]

[tex]T_{t}=(580*9.8*2.1)+(75.0*9.8*4.20)[/tex]

[tex]T_{t}=15023.4 Nm[/tex]

This results in a torque of 15023.4 Nm being applied on the bolt by the worker and the weight of the beam.

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From 0.08 to 150 (or more) fold the mass of the Sun, stars' masses fall within this range.

The mass of a star affects its life cycle. Its life cycle is shorter the greater its bulk. The amount of available stuff in a star's nebula, the enormous cloud of gas and dust in which it was born, determines the star's mass.

The majority of the galaxy's stars are red dwarf stars, but they are too faint to be seen from Earth with the human eye and remain hidden in the background. Their lifespans, which are much longer than that of the sun, are prolonged by their limited brilliance.

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Answer:

Explanation:

false

The weight of the package is  mg=76.0N. In the formula , F = -kx, proportional constant k is called the spring constant.

A measure of the stiffness of the spring is known as spring constant . When a spring is stretched or compressed, then its length changes by an amount x from its equilibrium length. And then, it exerts a force F = -kx in a direction towards the equilibrium position.

a) Using Hooke’s law, we can find out:

k=(15kg)(9.8m/s 2 )/(0.12m)=1225N/m.

=1.23kN/m.

b) Given, f=2.00Hz=2.00cycles/sec  

Now, ω=2π(2.00)=4πrad/s

As we know that , ω= √k/m

=1225/​ (4πrad/s)²

=7.76 kg

Therefore, the weight of the package is  mg=76.0N.

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The tangential haste(velocity) of the block m1 on the amicable(frictionless) table is1.34 m/s.

The given parameters;

mass of the first block, m1 = 2 kg

mass of the alternate block, m2 = 5 kg

distance of block m1, R = 0.75 m

The net torque on both blocks is calculated as

T( net) = Iα

T2R2- T1R1 = Iα

where;

T ₁ is the (tension)pressure on first block

I is the moment of inertia of point mass

α is the angular acceleration

T1 = m1g m1a

T2 = m2g m2a

The acceleration of both blocks is calculated as follows

R( T2- T1) = MR ² x( a/ R)

R( T2- T1) = MRa

(T2- T1) = M*a

g( m2- m1) = a( M m1 m2)

Where,

M is the mass of string = 0

g( m2- m1) = a( m1 m2)

a = 1.88 m/ s ²

The speed of the block m1 is calculated as follows;

a = v ²/ r

v = ar

v = 1.88 *0.75

v = 1.34 m/ s

Therefore, the tangential velocity of the block m1 on the frictionless table is 1.34 m/s.

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The refractive index of glycerine as 1.31 and  the thickness of the film is 0.808 μm

Light incident normally on a thick glass plate covered in a thin layer of glycerine with a refractive index of 1.55

Δθ=2Πn₂t/λ + Π-Π

Δθ=4Πn₂t/λ

For constructive interference

refractive index of glycerine is 1.31

Δθ=2mΠ

2mΠ=4Πn₂t/λ1

t=mλ1/2n2=970m/2*1.2

For destructive interference

ΔΘ=(2m+1)Π

4Πn₂t/λ₂=(2m+1)Π

t=(2m+1)λ2/4n₂

2*2.4/970+1=4*1.2/776t

0.001237t=1

t=808.33 nm

Thickness is =0.808 μm

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Answer:

(d) the longer wavelength the lower the frequency:

V = λ * f

For a given velocity - λ and f are inversely related

The volume of water in the bowl is 33.51 L.

Given data :

radius = 2

Volume of a hemisphere = 2 /3 x π x [tex]r^{3}[/tex]

= 2 / 3 x π x [tex]2^{3}[/tex]

= 33.51 L

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Answer:

D

Explanation:

A battery must they include in their apparatus.

A battery's positive terminal functions as the cathode and its negative terminal as the anode while it is supplying electricity. The source of the electrons that will move from the terminal labeled "negative" to the terminal labeled "positive" is an external electric circuit.

Redox reactions transform high-energy reactants into lower-energy products when a battery is coupled to an external electric load, and the free-energy difference is sent to the external circuit as electrical energy.

In the past, a device made of numerous cells was specifically referred to as a "battery," but today, devices made of a single cell are also included in this definition.

Therefore, A battery must they include in their apparatus.

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If n1 = n2 and n is relatively large, then the t test is relatively robust against violations of the assumptions of homogeneity of variance and normality. (Option A)

A t-test refers to an inferential statistic which is used to determine if there is a significant difference between the means of two groups and how they are related. According to the studies, t tests are remarkably robust to violations of a number of assumptions providing that the two sample sizes are equal or nearly equal and the assumed underlying population distributions are of the same or nearly same shape. T-test are found to be robust against deviation from normality and unequal variance. The test is in doubt only when there can be serious outliers, when sample sizes are small, and distributions are far from normal.

Note: The question is incomplete as it is missing options which are A) violations of the assumptions of homogeneity of variance and normality B) violations of random samples C). traffic violations D) violations by the forces of evil.

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The centripetal acceleration of the race car is 14.22m/s².

centripetal acceleration, the acceleration of a body traversing a circular path. Since velocity is a vector quantity (that is, it has magnitude, speed, and direction), when a body moves along a circular path, its direction is constantly changing, and thus its speed also changes and acceleration occurs. The acceleration is directed radially towards the center of the circle. The centripetal acceleration ac has a magnitude equal to the square of the velocity v of the body along the curve divided by the distance r from the center of the circle to the moving body; that is, ac = v²/r. Centripetal acceleration has units of meter per second squared.

v=80m/s

r=450m

a=80²/450=14.22m/s²

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Over the course of many billion years, if you were to monitor this star cluster, you would initially see a lot of supernovae, then none.

The enormous stellar explosion known as a supernova. Supernovae come in a variety of forms, according to scientists. In the final phase of the lives of huge stars which are least eight times bigger than our Sun, one form of supernova known as a "core-collapse" supernova occurs.

Supernovae may be split into two major types, Type I and Class Ii, depending to the way wherein they detonate. In addition to being up to three times lighter than Type II supernovae, Type I supernovae are distinct than Iii supernovae in that its spectra lack hydrogen lines.

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Answer:

c=f⋅λ  (The speed of light is directly proportional to f and λ).

Explanation:

A great strength of correlational research is the -fact that it occurs in real-world settings.

Correlational research is a form of non-experimental research methodology that employs statistical analysis to investigate the link between two variables. The impacts of unrelated factors on the variables under inquiry are not investigated by correlational research designs.

Characteristics-

1.Non-experiment: It implies that in order to support or refute a theory, researchers do not necessarily need to modify variables using a scientific technique.

2.Backward-looking: Correlational research solely considers historical information and keeps track of past events. It is measured and used by researchers to identify historical patterns between two variables.

3.Dynamic: Correlational research's patterns between two variables are never static and are constantly evolving. Due to numerous causes, two variables with a history of negative correlation studies may eventually show a positive correlation relationship.

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The correct descriptions corresponds to the sclera is It is made of dense tissue to help protect the eye.

Hence, Option A is correct.

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It is false to say that speed of pulse remains v after adding the second weight w on the vertical string.

We know very well that speed of transverse wave v in a string is given by:

v=√T / √μ

where,

T represents the tension in the string

μ represents the linear mass density defined for the string

Now, in the given situation,

when weight is  hanging on light vertical string is W, speed of the wave v is :

v=√W / √μ ----(eq1)

On addition of  an additional weight of W, speed of the wave becomes v ' as :

v′ = √2W /√μ -----(eq2)

After comparing eq1 and eq2, we observe that

after addition of same amount of weight in the given light string, speed will increase by √2 times the previous speed.

Hence, the given statement is false.

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The impedance of a series lrc circuit with a resistance of 18 ohms,The impedance is 27.88Ω.

Calculation:-

The impedance is given by,

[tex]Z = \sqrt{R^{2}+(wL -\frac{1}{wC})^{2} }[/tex]

The angular frequency can be written as,

W= 27[tex]\pi[/tex]  w = 2[tex]\pi[/tex] (120) = 753.98rad/s

We can calculate the impedance as,

=  Z = √(18)² + ((753.98)(0.03) - 1/(753.98)(1 x 10⁻³)² = 27.88Ω.

Impedance is the overall resistance of a circuit to current or a measure of how well it impedes the flow of charge. This is similar to resistance but also takes into account capacitance and inductance. An ohm is a unit of measurement for impedance. Impedance and resistance are similar concepts.

Both describe how a component resists or resists the flow of current. Resistance is the measurement of voltage divided by the resistance of the resistor. Impedance is a generalized concept of voltage divided by current in each component.

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The temperature rise the second cylinder B is 5/3 times the temperature in the cylinder A.

The heat source for both cylinders was:

ΔQ₁ = ΔQ₂  .....eq 1

Gas will expand in a cylinder with a free piston so that the pressure is always constant.

P = constant

Then,

ΔQ₁ = n.Cp.ΔT

ΔQ₁ = n.Cp.T₀  .....eq 2

With Fixed piston for cylinder (constant volume process),

V = constant

ΔQ₁ = n.Cv.ΔT  .....eq 3

From eq 1

n.Cp.T₀  =  n.Cv.ΔT

ΔT = (Cp/Cv) . T₀

ΔT = γ T₀

For the monatomic gas (γ = 5/3)

ΔT = 5/3 T₀

Thus, the temperature rise the second cylinder B is 5/3 times the temperature in the cylinder A.

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When you look at a distant rainbow, you see "a single color" from every individual water drop that makes up the bow.

The combination of sunlight and atmospheric factors produces a rainbow.

Thus, when you look at a distant rainbow, you see "a single color" from every individual water drop that makes up the bow.

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The object travelled 176.4 meters in the first 6 seconds of its descent. = 176.4 m. Therefore, the object's travel distance is 176.4 meters.

Distance, which is a scalar quantity, describes "how much ground an object has covered" while moving. The term "how far out of place an object is" relates to displacement, a vector number that describes the total change in position of the object.

If the scale is expressed verbally, such as "1 inch = 1 mile," then you can calculate the distance by simply measuring it with a ruler. If the scale, for instance, reads 1 inch Equals 1 mile, then the actual distance between two places on the ground is that amount of miles.

Knowing an object's distance allows us to determine its actual size. We can gauge how much space an object occupies in the sky.

   = 0 +1/2 (9.8) x 6²

   =1/2 x 352.8

  = 176.4

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d. Just before it is released, the box has twice as much elastic potential energy as before

When a spring is compressed, it stores potential energy in the form of elastic potential energy. The amount of elastic potential energy stored in the spring is given by the formula:

E = 1/2 * k * x^2

where E is the elastic potential energy, k is the force constant of the spring, and x is the distance the spring is compressed.

Therefore, if we compress the spring at a distance of 2x instead of x, the elastic potential energy stored in the spring will be twice as much. This means that just before the box is released, it has twice as much elastic potential energy as before.

Increasing contractility Dehydration Dehydration Decreased venous Teturn Sympathetic stimulation Increasing EDV Stress Acute exercise Increasing afterload Increased heart rate.

Hypertension increases afterload causing stroke volume to decrease. Hypertension refers to high or increased blood pressure. The afterload refers to the arterial pressure into which the stroke volume is ejected by the heart.

This is due to the fact that the aortic valve can not open unless the pressure generated in the left ventricle is higher compared to the elevated blood pressure in the aorta.

Therefore, Increasing contractility Dehydration Dehydration Decreased venous Teturn Sympathetic stimulation Increasing EDV Stress Acute exercise Increasing afterload Increased heart rate.

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Both atom emit a photon with a wavelength of 121.6 nm right after colliding. Atomic speed is defined as v = 44.2 * 103 m/s.

The rate at which site of an object shifts in any axis. Speed is described as the ratio of the distance covered to the time required to cover that length.

That really is speed Equals distance time. Alternatively, you can calculate the time by dividing the distance traveled by the speed. You can figure out the third input if you know one of the inputs. For instance, if a car drives 120 miles in 2 hours, we may calculate the speed as 120 x 2 = 60 kilometers per hour.

wavelength λ=121.6nm.

Energy, K=E

1/2mv*v = hc/λ

V² = hc/2λ

v²= 2(6.62*10⁻³⁴)(3*10⁸)/ (1.67*10⁻²⁷) (121.6*10⁻⁹)

v = 44.2 * 10³m/s

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A light pulse is a flash. Lasers and related devices have amazing potential for generating light pulses with very specific properties. There are various techniques for using lasers to generate nanosecond, picosecond and even femtosecond pulses.

Light energy is a form of kinetic energy that has the ability to make some kind of light visible to the human eye. Light is defined as a form of electromagnetic radiation emitted by hot objects such as lasers, incandescent bulbs, and the sun. Light contains photons, which are tiny packets of energy.

(a) Energy of photon = planck' constant x fequency

                                    =6.6x10^-34 x4.69 x10^14 J

(b) Energy of 5.0x10^17 photons = 6.6x10^-34 x 4.69x10^14 x5.0x10^17

The energy of a single photon is: hν or = (h/2π)ω where h is Planck's constant: 6.626 x 10-34 Joule seconds. Photons in visible light contain about 10-19 Joules per second in the beam.

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