The visible spectrum of sunlight shows a range of colors from red to violet. This spectrum has numerous dark lines spread throughout it. Noting that the surface of the Sun is much cooler than the interior, so that the surface is comparable to a cool gas through which light passes, which of the following statements correctly explains the dark lines?
a. The cooler, denser surface material scatters certain wavelengths of light, forming dark lines.
b. The atoms at the surface absorb certain wavelengths of light, causing the dark lines at those wavelengths.
c. The atoms in the Sun’s interior emit light of specific wavelength, so that parts of the spectrum are dark.
d. The atoms at the surface are excited by the high interior temperatures, so that the dark lines are merely wavelengths at which those atoms don’t emit energy.

Answer:

N = 25795 loops

Explanation:

The magnetic field of a solenoid can be calculated by using the following formula:

[tex]B = \frac{\mu NI}{L}\\N = \frac{BL}{\mu I}[/tex]

where,

N = No. of loops = ?

B = Magnetic Field = 0.78 T

L = Length of solenoid = 32 cm = 0.32 m

I = Current = 7.7 A

μ = permeability of free space = 4π x 10⁻⁷ N/A²

Therefore,

[tex]N = \frac{(0.78\ T)(0.32\ m)}{(4\pi\ x\ 10^{-7}\ N/A^2)(7.7\ A)}\\[/tex]

N = 25795 loops

Answer:

t = 0.4 seconds

Explanation:

Given that,

Mass of the object, m = 2 kg

Initial speed of the object, u = 3 m/s

Finally, it stops, v = 0

Constant force applied to the object, F = 15 N

We know that,

Force, F = ma

[tex]F=\dfrac{m(v-u)}{t}\\\\t=\dfrac{m(v-u)}{F}\\\\t=\dfrac{2\times (0-3)}{15}\\\\=0.4\ s[/tex]

So, it will take 0.4 seconds to stop the mass.

Answer:

6.726 m/s

Explanation:

Given that

Applied force, F = 870 N

Distance moves by the force, d = 1.3 cm = 0.013 m

Mass of the hand, m = 0.50 kg

From the given values, first thing is to find the work done by the force. Work done is given as

W = fd.

W = 870 * 0.013

W = 11.31 J

To find the velocity, next we use the formula for finding Kinetic Energy

K.E = 1/2mv²

Where K.E = 11.31

11.31 = 1/2 * 0.5 * v²

22.62 = 0.5v²

v² = 45.24

v = √45.24

v = 6.726 m/s

To break the board with a blow from the hand the speed of the hand will be [tex]v=6.726\ \frac{m}{s}[/tex]

Speed is defined as the distance traveled by any object with respect to the time.

Now it is given that

Applied force, F = 870 N

Distance moves by the force, d = 1.3 cm = 0.013 m

Mass of the hand, m = 0.50 kg

From the given values, first thing is to find the work done by the force. Work done is given as

[tex]W=F\times d[/tex]

[tex]W=870\times 0.013[/tex]

W = 11.31 J

To find the velocity, next we use the formula for finding Kinetic Energy

[tex]KE=\dfrac{1}{2}mv^2[/tex]

Where K.E = 11.31

[tex]11.31=\frac{1}2}\times 0.5\times v^2[/tex]

[tex]0.5v^2=22.62[/tex]

[tex]v^2=45.24[/tex]

[tex]v=6.726\ \ \frac{m}{s}[/tex]

Hence to break the board with a blow from the hand the speed of the hand will be [tex]v=6.726\ \frac{m}{s}[/tex]

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Answer:

The limitations of sending information using electromagnetic waves is that when the electromagnetic waves move outward in all directions, wave transmitters need to be focused to transmit their signals to a single specified location.

Answer:

pls check

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Answer:

isobaric

Explanation:

According to the attached figure, the process would be isobaric as the gas would be expanded at the time when it maintains the constant pressure

The ideal gas law derives

PV = nRT

As the flame is there at the bottom side so atoms or molecules of gas would get heat up slowly also their temperature would be increased. Thus in the case when piston would not be permitted to move so the pressure would rise having maintaining the constant volume and after this the process could be isochronic but in the given case, the piston would be permitted to move slowly upward so that there is a rise in the volume. However, the gas particles would be adjust themselves in order to maintain constant pressure so the given process represent isobaric  

Answer:

2.8s

Explanation:

=>a = v-u/t

=> t = v - u / t

= 28-0 / 10

= 2.8 s

Answer:

the answer is B from negative pole to positive pole

Answer:

123.2newtons

Explanation:

weight =mass × gravity

w= m×g

gravitational pull is approximately 10N/Kg

w= 12.32kg×10n/kg

=123.2newtons or 12.3N

Answer:

B) Yes, but only those electrons with energy greater than the potential difference established between the grid and the collector will reach the collector.

Explanation:

In the case when the collector would held at a negative voltage i.e. small with regard to grid So yes the accelerated electrons would be reach to the collecting plate as the kinetic energy would be more than the potential energy that because of negative potential

so according to the given situation, the option b is correct

And, the rest of the options are wrong

Answer:

A. 234

Explanation:

An alpha particle is a Helium atom which has a mass number of 4 and atomic number of 2. So, an alpha particle decay cause the mass number to decrease by 4 units.

So 238 - 4 = 234

The answer is A

Answer:

The frecuency is 1.2*10¹¹ Hz.

Explanation:

Wavelength is the minimum distance between two successive points on the wave that are in the same state of vibration. It is expressed in units of length (m).

Frequency is the number of vibrations that occur in a unit of time, that is, how many peaks or valleys are repeated in a unit of time. Its unit is s – 1 or hertz (Hz).

The propagation speed is the speed with which the wave propagates in the medium, that is, it is the magnitude that measures the speed at which the wave disturbance propagates along its displacement. It relates the wavelength (λ) and the frequency (f) inversely proportional using the following equation:

v = f * λ.

In this case:

Replacing:

300,000,000 m/s= f* 0.0025 m

Solving:

f= 300,000,000 m/s ÷0.0025 m

f= 1.2*10¹¹ [tex]\frac{1}{s}[/tex] =  1.2*10¹¹ Hz

The frecuency is 1.2*10¹¹ Hz.

Answer:

The tempature changes, and the envronment chnages because of this, therefore making tempature changes in a graph.

Explanation:

sorry if this isnt good

Temperature variations in a graph occur as a result of changing environmental conditions and changing temperature.  

Temperature is a physical quantity which measures hotness and coldness of a body. Temperature measures the degree of vibration of molecule in a body. Temperature is measured in centigrade (°C), Fahrenheit (°F) and Kelvin (K) in which Kelvin (K) is a SI unit of temperature. Absolute scale of temperature means Kelvin scale of temperature. relation between Kelvin(K) and centigrade (°C), °C= K - 273.15 from equation, 273.15 K means 0 °C, which is freezing point of water (ice). when we give temperature to the body, its molecule or atom absorbs thermal energy and vibrate about their mean position. Amplitude of vibration get increases as we go on increasing temperature and for higher temperature force of attraction between molecules gets weaker. Hence for higher temperature, due to weaken the force of attraction between molecule, solid goes into liquid state. and further increase in temperature liquid goes into gaseous state.

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Answer:

Explanation:

1.The focal length is equal to half of the …………….

b . The radius of Curvature

2.The point on principal axis at which parallel rays; coming from infinity; converge after reflection is called the …………….

a. Principal Focus

3.Which of the following best describes the image formed by a plane mirror?

c. Virtual, erect and the same size as object

4.Which of the following best describes the image formed by a convex mirror?

a. Virtual, erect and magnified

Answer:

T = 4 N

Explanation:

Given that,

Weight of a car, W = 80 N

We know that,

Weight = mg

80 = 10m

m = 8 kg

If the acceleration of the car is 0.5 m/s², then force becomes,

F = 8 × 0.5

F= 4 N

So, the required tension force is 4 N.

Answer:

E = 420.9 N/C

Explanation:

According to the given condition:

[tex]Net\ Force = 2(Magnetic\ Force)\\Electric\ Force - Magnetic\ Force = 2(Magnetic\ Force)\\Electric\ Force = 3(Magnetic\ Force)\\qE = 3qvBSin\theta\\E = 3vBSin\theta[/tex]

where,

E = Magnitude of Electric Field = ?

v = speed of charge = 230 m/s

B = Magnitude of Magnetic Field = 0.61 T

θ = Angle between speed and magnetic field = 90°

Therefore,

[tex]E = (3)(230\ m/s)(0.61\ T)Sin90^o[/tex]

E = 420.9 N/C

Answer:

dynamic equilibrium

Explanation:

Substances transition between the reactants and products at equal rates, meaning there is no net change. Reactants and products are formed at such a rate that the concentration of neither changes.

Answer:

Graph C

Explanation:

With the same force and more mass, the position in time will still be parabolic

i.e.  x = ½at², but the rate of acceleration will be lower so the position curve will be broader.

Answer:

[tex]F_2=1.3\times 10^{-7}\ N[/tex]

Explanation:

Given that,

Initial force, [tex]F=5.2\times 10^{-7}\ N[/tex]

distance, d = 2 m

New distance, d' = 4 m

We need to find the new force. The electrostatic force between two charges is given by :

[tex]F=k\dfrac{q_1q_2}{d^2}[/tex]

So,

[tex]\dfrac{F_1}{F_2}=(\dfrac{d_2}{d_1})^2\\\\\dfrac{F_1}{F_2}=(\dfrac{4}{2})^2\\\\\dfrac{F_1}{F_2}=4\\\\F_2=\dfrac{F_1}{4}\\\\F_2=\dfrac{5.2\times 10^{-7}}{4}\\\\F_2=1.3\times 10^{-7}\ N[/tex]

So, the new force is equal to [tex]1.3\times 10^{-7}\ N[/tex].

Answer:

C. Sleep Apnea

Explanation:

Sleep Apnea is when someone who snores and stops breathing while sleeping

Someone who snorts and stop breathing during sleep may be suffering from Sleep Apnea. Hence, option (c) is correct.

Breathing repeatedly stops and begins while you sleep, which is a frequent symptom of sleep apnea. Your body may not receive enough oxygen as a result.

There are two different forms of sleep apnea.

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Answer:

D

Explanation:

Coulomb's law states that the electrical force between two charged objects is directly proportional to the product of the quantity of charge on the objects and inversely proportional to the square of the separation distance between the two objects.

Answer:

Part 1:

Option B is correct (It will remain unchanged).

Part 2:

Option C is correct (It will increase by a factor of √ 2)

Part 3:

Option E is correct (It will be half as fast/long.)

Part 4:

Option C is correct (It will increase by a factor of √ 2.)

Explanation:

Formula we are going to use:

V=f*λ

Where:

V is the speed of Sound

f is the frequency of wave

λ is the wavelength.

The speed of wave , tension and linear density have following relation:

[tex]V=\sqrt{F/\rho}[/tex]

Where:

V is the speed of Sound (Initial)

F is the tension in string (Initial)

[tex]\rho[/tex] is the linear density of string (Constant)

Terms:

V' is the new speed

f' is the new frequency

λ' is the wavelength

Solution:

Part 1:

From [tex]V=\sqrt{F/\rho}[/tex]:

Speed of Sound is independent of the frequency of shaking so speed well remain unchanged.

Option B is correct (It will remain unchanged)

Part 2:

If F'=2F then

[tex]V=\sqrt{F/\rho}[/tex]

[tex]V'=\sqrt{F'/\rho}\\V'=\sqrt{2F/\rho}\\V'= \sqrt{2} * \sqrt{F/\rho}\\V'=\sqrt{2}V[/tex]

Option C is correct (It will increase by a factor of √ 2)

Part 3:

Formula we are going to use:

V=f*λ

Given f'=2f,

Even though frequency is doubled we will keep velocities same. V=V' in order to find the changing wavelength.

V'=f'*λ'

f*λ=f'*λ'

f*λ=2f*λ'

Solving above Equation:

λ'=λ/2

Option E is correct (It will be half as fast/long.)

Part 4:

T'=2T means [tex]V'=\sqrt{2}V[/tex] (From Part 1)

f'=f

Now:

V'=f'*λ'

[tex]\sqrt{2}f*\lambda=f'*\lambda '\\\sqrt{2}f*\lambda=f*\lambda '\\ \lambda '=\sqrt{2}*\lambda[/tex]

Option C is correct (It will increase by a factor of √ 2.)

Answer:

[tex]3 \times 10 {}^6[/tex]

It needs fuse of size 3A to be operated

Answer: 10 A

Explanation: The 3a and 5 a will blow immediately which would not allow you to use the coffee machine

The 13 a is too high and might lead to damage to the coffee machine or a fire being started

10 A is perfect because its low enough that if their was a power surge it would be blown without damaging anything else and it is high enough to let the coffee machine work without any trouble

Answer:  

Newton's second law of motion describes the relationship between force and acceleration. They are directly proportional. If you increase the force applied to an object, the acceleration of that object increases by the same factor. In short, force equals mass times acceleration.

Explanation:

Answer:

the bus can travel 24.54 km before the flywheel has to be spun up to speed again

Explanation:

 Given the data in the question;

mass of wheel m = 1600 kg

radius of the fly wheel r = 0.650 m

angular speed of the wheel ω = 4000 rev/min = 418.879 rad/s

Average speed of the bus v = 40 km/h =  11.1111 m/s

Power p = 18 hp = 13428 watt

So moment of inertia of the fly wheel is;

[tex]I[/tex] = [tex]\frac{1}{2}[/tex]mr²

we substitute

[tex]I[/tex] = [tex]\frac{1}{2}[/tex] × 1600 kg × (0.650 m)²

[tex]I[/tex] = 338 kgm²

So, the rotational energy of the bus will be;

[tex]E_r[/tex] = [tex]\frac{1}{2}[/tex][tex]I[/tex]ω²

we substitute

[tex]E_r[/tex] = [tex]\frac{1}{2}[/tex] × 338 kgm²  × ( 418.879 rad/s )

[tex]E_r[/tex] = 29652675.212329 J

relation of power to energy

P = E / t

but we know that time t = distance / velocity

t = d/v

∴

P = E / ( d/v)

we solve for distance (d)

P = Ev / d

Pd = Ev

d = Ev / P

so we substitute

d = [( 29652675.212329 J )( 11.1111 m/s )] / [ 13428 W ]

d = 24536.33 m

d = 24.54 km

Therefore, the bus can travel 24.54 km before the flywheel has to be spun up to speed again

Answer:

i҈ d҈o҈n҈t҈ k҈n҈o҈w҈ w҈h҈a҈t҈ y҈o҈u҈r҈ s҈a҈y҈i҈n҈v҈ b҈c҈h҈

Answer:

[tex]m^{3}kg^{-1} s^{-2}[/tex]

Explanation:

Answer:

9013 m/s

Explanation:

hope it helped!!!

the answer is the first one