Please help me if you can.
I can't figure out how the answer for number 30 is C and 31 is C. My question is how did they get that answer?

Answer:

V = f x λ

Explanation:

The options are confusing

Answer:

  The wavelength of the wave is [tex]1.06\times10^6 m[/tex]  

Explanation:

Lets calculate

We know an electromagnetic wave is propagating through an insulating magnetic material of dielectric constant K and relative permeability [tex]K_m[/tex] ,then the speed of the wave in this dielectric medium is [tex]\nu[/tex] is less than the speed of the light c and is given by a relation

               [tex]\nu=\frac{c}{\sqrt{KK_m} }[/tex]  --------- 1

In case the electromagnetic  wave propagating through the insulating magnetic material , the amplitudes of electric and  magnetic fields are related as -

             [tex]E_m_a_x= \nu B_m_a_x[/tex]

The magnitude of the 'time averaged value' of the pointing vector is called the intensity of the wave and is given by a relation

                       [tex]I = S_a_v[/tex]

                        [tex]\frac{E_m_a_xB_m_a_x}{2K_m\mu0}[/tex]----------- 3

now , we will find the speed of the propagation of an electromagnetic wave by using equation 1

[tex]\nu=\frac{c}{\sqrt{KK_m} }[/tex]

Putting the values ,

   =[tex]\nu= \frac{3.00\times10^8}{\sqrt{(3.64)(5.18)} }[/tex]

 =[tex]0.6908\times10^8m/s[/tex]

 = [tex]6.91\times10^7m/s[/tex]

Now , using this above solution , we will find the wavelength of the wave -

     [tex]\lambda=\frac{\nu}{f}[/tex]

    Putting the values from above equations -

  [tex]\frac{6.91\times10^7m/s}{65.0Hz}[/tex]

        [tex]\lambda= 1.06\times10^6 m[/tex]

Hence , the answer is [tex]\lambda= 1.06\times10^6 m[/tex]

Answer:

a) 500 J

Explanation:

Potential energy can be defined as an energy possessed by an object or body due to its position.

Mathematically, potential energy is given by the formula;

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

Where,

P.E represents 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.

In Science, the potential energy possessed by an object or body is the same as the work done by the object or body.

Since we know that the object possessed 500 Joules of potential energy; it would ultimately require to do a work of 500 Joules to lift the object.

Mathematically, work done = force * distance

But force = mass * acceleration due to gravity

F = mg; d = h

Substituting into the work done formula, we have;

Hence, Workdone = Fd = mgh

Answer:17: A wave can be defined as follows: It is important to realize that a wave is quite a different object than a particle. A baseball thrown though a window transfers energy from one point to another, but this involves the movement of a material object between two points.

Explanation:

18: In this way, we classify waves into electromagnetic and mechanical waves. The main difference between mechanical and electromagnetic waves is that electromagnetic waves do not require a medium to propagate whereas mechanical waves require a medium in order to propagate.

Answer:

Option A. 10¯⁶

Explanation:

To know which option is correct, we must bear in mind, the relationship between micro coulomb (μC) and coulomb (C). This is given below:

Recall:

1 μC = 10¯⁶ C

Therefore, to convert micro coulomb (μC) to coulomb (C), multiply the value given in micro coulomb (μC) by 10¯⁶.

Thus, option A gives the correct answer to the question.

Answer:

Potential energy is related to mass and height. More context is required otherwise the answer here is an equation with several unknowns. PE = mgL(1 – COS θ) where θ is the angle away from the vertical and L is the length of the string.

Explanation:

Answer:

The bright blue and black colors represent the following:

Constructive and destructive interference are represented by the blue and black colors, respectively. When two water waves collide constructively, the resultant wave is bright blue, while when they collide destructively, the resultant wave is black in color.

Explanation:

   When two propagating waves with the same frequency (say, [tex]\nu[/tex]) and wavelength (say,[tex]\lambda[/tex]) but slightly different amplitudes (say, A 1 and A 2) traveling in the same direction interfere or are superimposed on each other (that is incident at the same point or object), a third resultant wave with a different amplitude (increased or decreased) but same wavelength and frequency is generated.  

The direction difference between the two waves determines whether they intervene constructively (increasing the amplitude of the resultant wave) or destructively (increasing the amplitude of the resultant wave) (decreased amplitude of the resultant wave). To put it another way, when the difference in direction between the two waves is of the form -

      [tex]\Delta x = n\lambda , n=0,1,2,.....[/tex] is the order of interference.

The two waves are then assumed to be in phase, and the interference is constructive, resulting in the resultant wave having a larger amplitude (which is the sum of the two amplitudes [tex]A_1 +A_2[/tex]  also known as a maxima). When the difference in direction between the two waves is in the form -

  [tex]\Delta x = (2n-1)\frac{\lambda}{2} , n=0,1,2,.....[/tex] is the order of interference.

The two intervening waves are then said to be out of phase, and the interference is disruptive, resulting in the resultant wave having a lower amplitude (which is the difference between the two amplitudes [tex]A_1+A_2[/tex], also known as a minima).

Hence , the graphical representation of constructive (blue )and destructive (black) is attached.

Answer:

Perpendicular ; Parallel

Answer:

A. Material that electric current passes easily through.

Explanation:

Answer:

The coefficient of performance of the refrigerator is 2.251.

Explanation:

In this case, the coefficient of performance of the refrigerator ([tex]COP[/tex]), no unit, is equal to the ratio of the heat rate received from the water to the power needed to work, that is:

[tex]COP = \frac{\dot Q_{L}}{\dot W}[/tex] (1)

[tex]COP = \frac{\rho\cdot V\cdot c_{w}\cdot \Delta T}{\dot W \cdot \Delta t}[/tex] (2)

Where:

[tex]\dot Q_{L}[/tex] - Heat rate received from the water, in watts.

[tex]\dot W[/tex] - Power, in watts.

[tex]\rho[/tex] - Density of water, in kilograms per cubic meter.

[tex]V[/tex] - Volume of water, in cubic meters.

[tex]c_{w}[/tex] - Specific heat of water, in joules per kilogram-degree Celsius.

[tex]\Delta T[/tex] - Temperature change, in degrees Celsius.

[tex]\Delta t[/tex] - Cooling time, in seconds.

If we know that [tex]\rho = 1000\,\frac{kg}{m^{3}}[/tex], [tex]V = 1.45\times 10^{-3}\,m^{3}[/tex], [tex]c_{w} = 4187\,\frac{J}{kg\cdot ^{ \circ}C}[/tex], [tex]\Delta T = 10\,^{\circ}C[/tex], [tex]\dot W = 10.7\,W[/tex] and [tex]\Delta t = 2520\,s[/tex], then the coefficient of refrigeration of the refrigerator is:

[tex]COP = \frac{\rho\cdot V\cdot c_{w}\cdot \Delta T}{\dot W \cdot \Delta t}[/tex]

[tex]COP = 2.251[/tex]

The coefficient of performance of the refrigerator is 2.251.

300

could i get brainiest

The distance - time graph of the humming bird is missing, so i have attached it.

Answer:

Instantaneous velocity = 0.5 m/s

Explanation:

From the attached graph, at time t = 1 s, the corresponding distance is 0.5 m.

Instantaneous velocity is the velocity at that point.

Thus;

Instantaneous velocity = 0.5/1

Instantaneous velocity = 0.5 m/s

Answer:

-17.5 nC

Explanation:

charge A = -30 nC

charge B = -5 nC

After adding them it would be the average of the two charges because of the getting same voltage difference. so

c = (-30+(-5)) / 2 nC

c= -17.5 nC

answer is -17.5 nC

Answer:

V= 0.25L

Explanation:

Answer:

3 m/s²

Explanation:

Initial Velocity, u = 18

Final velocity, v = 36

Time, t = 6 seconds

Acceleration is the change in velocity of a body with time. It obtained using the relation :

Acceleration = (v - u) / t

Acceleration = (36 - 18) / 6

Acceleration = 18 / 6

Acceleration = 3m/s²

Hence, acceleration of the skier is 3m/s²

Answer:

it depends on the medium :D

Answer:

Valence electrons are outer shell electrons with an atom and can participate in the formation of chemical bonds. In single covalent bonds, typically both atoms in the bond contribute one valence electron in order to form a shared pair. The ground state of an atom is the lowest energy state of the atom.

Answer:

k and...

Explanation:

Answer:

no thank you.

explanation: Do not want to

Answer:

The distance between the Earth and the Sun is:

1.5 multiplied by 10 raised to the power 8 km

Explanation:

(5.0 x 10²) x (3.0 x 10⁸) = 1.5 x 10¹¹ meters = 1.5 x 10⁸ km.

Answer:

2000J

Explanation:

The formula for work is W=Force x Distance

W=FxD

W=500N x 4m

W=2,000 Joules

Answer:

The potential energy is zero since the rock isn't moving.

Answer:

The resistor has a resistance of 10.667 ohms.

Explanation:

By Ohm's Law, voltage ([tex]V[/tex]), in volts, is directly proportional to the current ([tex]i[/tex]), in amperes, and by definition of power ([tex]\dot W[/tex]), in watts, we have the following formula:

[tex]\dot W = i^{2}\cdot R[/tex] (1)

Where [tex]R[/tex] is the resistance, in ohms.

If we know that [tex]\dot W = 24\,W[/tex] and [tex]i = 1.5\,A[/tex], then the resistance of the resistor is:

[tex]R = \frac{\dot W}{i^{2}}[/tex]

[tex]R = 10.667\,\Omega[/tex]

The resistor has a resistance of 10.667 ohms.

Answer:

[tex]F_{elect} = \frac{kq_1q_2}{d^2}[/tex]

Explanation:

Consider the given variables:

Felect = Electrostatic Force between charged particles

k = Coulomb's Constant

q₁ = magnitude of first charge

q₂ = magnitude of second charge

d = distance between the charges

The relationship among these variables is given by the Coulomb's Law:

[tex]F_{elect} = \frac{kq_1q_2}{d^2}[/tex]

This is the relationship that contains k, q₁, q₂, d on the right-hand side and Felect on the left-hand side.

Answer:

2.5 m/s²

Explanation:

Given,

Initial speed ( u ) = 10 m/s

Final speed ( v ) = 20 m/s

Time ( t ) = 4 seconds

To find : Acceleration ( a ) = ?

Formula : -

a = ( v - u ) / t

a = ( 20 - 10 ) / 4

= 10 / 4

= 5 / 2

a = 2.5 m/s²

Therefore,

The acceleration of the scooter is 2.5 m/s²

Answer:

This type of motion is defined as the motion of an object in which the object travels in a straight line and its velocity remains constant along that line as it covers equal distances in equal intervals of time, irrespective of the duration of the time.

Explanation:

In Physics, uniform motion is defined as the motion, wherein the velocity of the body travelling in a straight line remains the same. When the distance travelled by a moving thing, is same at several time intervals, regardless of the time length, the motion is said to be uniform motion.