MCQs. How does the heat from the Sun reach the Earth.(options)a: conduction b: convertion c: radiation d: combustion.​

Answer: 28

Explanation:

Given

Circuit breaker current is [tex]I=20\ A[/tex]

Power of the light bulb is [tex]P=100\ W[/tex]

Voltage of the DC-circuit is [tex]V=120\ V[/tex]

If the resistance are connected in parallel, they must have same voltage i.e. 120 V

So, Resistance is given by

[tex]\Rightarrow R=\dfrac{V^2}{P}\\\\\Rightarrow R=\dfrac{120^2}{100}\\\\\Rightarrow R=144\ \Omega[/tex]

For the 20 A current and 120 V battery, net resistance is

[tex]\Rightarrow R_{net}=\dfrac{120}{20}\\\\\Rightarrow R_{net}=6\ \Omega[/tex]

Suppose there are n resistance in the circuit connected in parallel.

[tex]\Rightarrow \dfrac{144}{n}=R_{net}\\\\\Rightarrow n=\dfrac{144}{6}\\\\\Rightarrow n=28.8\approx 28\ \text{for current to be less than 20A}[/tex]

Thus, there can maximum of 28 bulbs.

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In geometry, the area can be defined as the space occupied by a flat shape or the surface of an object. The area of a figure is the number of unit squares that cover the surface of a closed figure.

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[tex] \huge\bold{T}[/tex]he speed of sound is maximum in solids. The speed of sound depends on the density of the medium through which it travels.The higher the density of the medium, the faster the propagation of sound. Since the density of solids is greater than that of liquids and gases, sound travels faster in solids. Also, the molecules in the solid medium are closer together than in liquids or gases, which allows sound waves to travel faster through it.

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Answer:

15 is the correct answer I.t.

Answer:

1.07 × 10⁸ m/s

Explanation:

Using the relativistic Doppler shift formula which can be expressed as:

[tex]\lambda_o = \lambda_s \sqrt{\dfrac{c+v}{c-v}}[/tex]

here;

[tex]\lambda _o[/tex] = wavelength measured in relative motion with regard to the source at velocity v

[tex]\lambda_s =[/tex] observed wavelength from the source's frame.

Given that:

[tex]\lambda _o[/tex] = 656.3 nm

[tex]\lambda_s =[/tex] 953.3 nm

We will realize that [tex]\lambda _o[/tex] > [tex]\lambda_s[/tex]; thus, v < 0 for this to be true.

From the above equation, let's make (v/c) the subject of the formula: we have:

[tex]\dfrac{\lambda_o}{\lambda_s}=\sqrt{\dfrac{c+v}{c-v}}[/tex]

[tex]\Big(\dfrac{\lambda_o}{\lambda_s} \Big)^2=\dfrac{c+v}{c-v}[/tex]

[tex]\dfrac{v}{c} =\dfrac{\Big(\dfrac{\lambda_o}{\lambda_s} \Big)^2-1}{\Big(\dfrac{\lambda_o}{\lambda_s} \Big)^2+1}[/tex]

[tex]\dfrac{v}{c} =\dfrac{\Big(\dfrac{656.3}{953.3} \Big)^2-1}{\Big(\dfrac{656.3}{953.3} \Big)^2+1}[/tex]

[tex]\dfrac{v}{c} =0.357[/tex]

v = 0.357 c

To m/s:

1c = 299792458 m/s

∴

0.357c = (299 792 458 × 0.357) m/s

= 107025907.5 m/s

= 1.07 × 10⁸ m/s

Answer:

amplitude

Explanation:

The loudness of a musical sound is a measure of the sound wave's ?

is amplitude explanation:- The loudness of a sound depends upon the amplitude.Loudness of a sound depends on the amplitude of the vibration producing that sound. Greater is the amplitude of vibration, louder is the sound produced by it. if you find this answer helpful please rate positive thank you so much.

area= length × length

area = 4m × 9m

ans 36

Answer:

doubled

Explanation:

When thrust is double so will the pressure I hope this helps

enjoy

Answer:

Explanation:

The one above is incorrect, and I know this is late. Even if it doesn't help you I hope it helps people in the future! YES I AM TALKING ABOUT YOU FUTURE PEOPLE!! I know this is the answer because I have taken 5.11 Quiz: Uncrewed Spacecraft in K12. There will only be the questions and correct answers below.

1. Which planetary body was Spirit designed to explore?

Mars.

2. What is the name of the most distant manmade object in space? (Credit: shathaadnan64/lak521)

Voyager 1.

3. Which group was designed to study Saturn? (Credit: Brainly User/snowballandtigoya1xa

Voyager 1, Huygens, and Cassini.

4. Why are scientists interested in exploring Mars?

Possible evidence of life.

5. What do interplanetary space missions study?

Planets in the solar system.

Have an amazing day!!

Answer:

the correct answer is B

Explanation:

The quantum numbers are the constants obtained when solving the Schrodinger equation, the first quantum number or principal quantum number (n), can take values ​​from zero to infinity.

This quantum number is placed as a coefficient in the quantum distribution.

In this case for phosphorus, the number is n = 3

the correct answer is B

Answer:

Magnetism is a physical phenomenon that manifests itself in a force acting between magnets or other magnetized or magnetisable objects, and a force acting on moving electric charges, such as in current-carrying cables. The force action takes place by means of a magnetic field, which is generated by the objects themselves or otherwise. There are natural and artificial magnets. All magnets have two poles called the north pole and the south pole. The north pole of one magnet repels the north pole of another magnet and attracts the south pole of another magnet; the same with south poles.  

Answer:

the answer is the explaination

Explanation:

Present beach erosion prevention methods include sand dunes, vegetation, seawalls, sandbags, and sand fences. Based on the research conducted, it is evident that new ways to prevent erosion must be obtained. Each way that is currently used has extensive negative effects on beaches and their natural tendencies.

Answer:

They will construct strong sea walls with the intent to protect the coastline and infrastructure that could be affected by erosion.

Explanation:

Answer:

[tex]\frac{1}{2}mR^2\omega^2[/tex]

Explanation:

The rotational kinetic energy of an object is given by [tex]KE_r=\frac{1}{2}I\omega^2[/tex], where [tex]I[/tex] is the object's moment of inertia/rotational inertia and [tex]\omega[/tex] is the object's angular speed.

What we're given:

Since no numerical value is given for any of these, it is implied the desired answer will be an equation in terms of the variables given.

Substituting [tex]I=MR^2[/tex]:

[tex]KE_r=\boxed{\frac{1}{2}mR^2\omega^2}[/tex]

Answer:

in this case around the loop the field points downwards on the outside and upwards on the inside

Explanation:

To find the direction of the magnetic field in a wire you must use the right hand rule.

The thumb points in the direction of the current flow and the other created fingers point in the direction of the magnetic field.

Therefore in this case around the loop the field points downwards on the outside and upwards on the inside

Answer:

B. They are inversely proportional to each other

[tex] \frac{momentum}{time} = force \\ \\ \frac{mass \times velocity}{time} = force \\ \\ \frac{mass \times velocity}{time} = mass \times acceleration[/tex]

Answer:

[tex]E=6.86\times 10^6\ N/C[/tex]

Explanation:

Given that,

Mass of the sphere, m = 2.1 g = 0.0021 kg

Charge, q = 3 nC

We need to find the magnitude of the electric field that balanced the weight of sphere. Let it is E. So,

qE = mg

[tex]E=\dfrac{mg}{q}[/tex]

Put all the values,

[tex]E=\dfrac{0.0021\times 9.8}{3\times 10^{-9}}\\\\E=6.86\times 10^6\ N/C[/tex]

So, the magnitude of the elecric field is [tex]6.86\times 10^6\ N/C[/tex].

Answer:

b. is the correct answer ....

Answer:

time perion=1/frequency

so here time period =1/262

let wavelength be x

speed of sound=wave length/time period

342=x/1/262

342=262x

342/262=x

1.30=x

therefore wavelength=1.30 metre

Explanation:

Answer:

(a) I = 1650000 A

(b) 4.125 T

Explanation:

Magnetic field, B = 5.5 T

distance, r = 0.06 m

(a) Let the current is I.

The magnetic field due to a long wire is given by

[tex]B =\frac{\mu o}{4\pi }\frac{2 I}{r}\\5.5= 10^{-7}\times \frac{2\times I}{0.06}\\I =1650000 A[/tex]

(b) Let the magnetic field is B' at distance r = 0.08 m.

[tex]B =\frac{\mu o}{4\pi }\frac{2 I}{r}\\B = 10^{-7}\times \frac{2\times 1650000}{0.08}\\B'= 4.125 T[/tex]

Answer:

The rotation rate is 15.3 rad/s.

Explanation:

maximum voltage, V = 120 V

Magnetic field, B = 1.5 T

length, L = 10.2 cm

width, W = 12.8 cm

Number of loops, N = 400

Let the rate of rotation is w.

The maximum voltage is given by

V = N B A w

120 = 400 x 1.5 x 0.102 x 0.128 x w

w = 15.3 rad/s

Answer:

10J

Explanation:

KE = (1/2)mv²

100J = (.5)(40kg)v²

v²=(100J)/(20kg)

v²= 5

KE = 5(.5)(4kg)

KE = 10J

Answer:

1.00 × 10⁴ pieces of pizza

Explanation:

Step 1: Calculate the energy needed to watch the Super Bowl.

We need to produce energy to make an HDTV work (175 W) for 4 hours. First, we will convert, 4 hours to seconds using the conversion factor 1 h = 3600 s.

4 h × 3600 s/1 h = 14400 s

The energy required is:

14400 s × 175 J/s = 2.52 × 10⁶ J

We can convert this to calories using the conversion factor 1 cal = 4.184 J.

2.52 × 10⁶ J × 1 cal/4.184 J = 6.02 × 10⁵ cal

Step 2: Calculate the calories that the person should consume

Assuming an efficiency of 20% for the human body, the calories that a person should consume are:

6.02 × 10⁵ cal × 100/20 = 3.01 × 10⁶ cal

Step 3: Calculate the number of pieces of pizza to be consumed

Each piece of pizza contains 300 cal.

3.01 × 10⁶ cal × 1 piece/300 cal = 1.00 × 10⁴ pieces

(a) 4.20 J

(b) 16.74 J

For a parallel plate vacuum capacitor with area A and whose plates are separated by by a distance of d, its capacitance C is given by;

C = A∈₀ / d              --------------------(i)

Where;

∈₀ = constant called permittivity of vacuum.

The energy U stored in such capacitor is given by;

U = [tex]\frac{1}{2}[/tex]CV²             ----------------------(ii)

or

U =  [tex]\frac{1}{2}[/tex](Q²/C)        -------------------(**)

Where;

V = potential difference or voltage across the plates.

Q = charge on the plates.

(a) If the charge is held constant

Combine equations (i) and (**) to give;

U =  [tex]\frac{1}{2}[/tex]Q² / (A∈₀ / d)     -----------------------(iii)

From the question;

The parallel plate capacitor has 8.40J energy stored and distance between plates is 2.30mm i.e

U = 8.40J

d = 2.30mm = 0.023m

Substitute these values into equation (iii)

8.40 =  [tex]\frac{1}{2}[/tex]Q² / (A∈₀ / 0.023)

8.40 =  [tex]\frac{1}{2}[/tex]Q² x (0.023 / A∈₀)

Multiply through by 2

2 x 8.40 = Q² x (0.023 / A∈₀)

16.80 = Q² x (0.023 / A∈₀)

Divide through by 0.023

16.80 / 0.023 = Q² x (0.023 / A∈₀) / 0.023

730.4 = Q² / (A∈₀)

Make Q² subject of the formula

Q² = 730.4(A∈₀)

Now, if the separation distance is decreased to 1.15mm and the voltage is held constant i.e

d = 1.15mm = 0.0115m

Q = constant [this means that Q² still remains 730.4(A∈₀) ]

The energy stored is found by substituting these values of d and Q² into equation (iii) as follows;

U =   [tex]\frac{1}{2}[/tex]Q² / (A∈₀ / d)

U = [tex]\frac{1}{2}[/tex](730.4(A∈₀)) / (A∈₀ / 0.0115)

U = [tex]\frac{1}{2}[/tex](730.4(A∈₀))(0.0115 / A∈₀)

U = [tex]\frac{1}{2}[/tex](730.4)(0.0115)

U = 4.20J

Therefore, the energy stored if the charge Q on the plates is held constant is 4.20 J

(b) If the voltage is held constant

Combine equations (i) and (ii) to give;

U =  [tex]\frac{1}{2}[/tex](A∈₀ / d)V²     -----------------------(iv)

From the question;

The parallel plate capacitor has 8.40J energy stored and distance between plates is 2.30mm i.e

U = 8.40J

d = 2.30mm = 0.023m

Substitute these values into equation (iv)

8.40 =  [tex]\frac{1}{2}[/tex](A∈₀ / 0.023)V²

Multiply through by 2 x 0.023

2 x 0.023 x 8.40 = (A∈₀)V²

2 x 0.023 x 8.40 = (A∈₀)V²

0.385 = (A∈₀)V²

Make V² subject of the formula

V² = 0.385/(A∈₀)

Now, if the separation distance is decreased to 1.15mm and the voltage is held constant i.e

d = 1.15mm = 0.0115m

V = constant [this means that V² still remains 0.385/(A∈₀) ]

The energy stored is found by substituting these values of d and V² into equation (iv) as follows;

U =  [tex]\frac{1}{2}[/tex](A∈₀ / 0.0115)[0.385/(A∈₀)]  

U = [tex]\frac{1}{2}[/tex](0.385/0.0115)

U = 16.74

Therefore, the energy stored if the voltage V across the plates is held constant is 16.74 J

SOLVED DOWN BELOW

Explanation:

In series the same current goes thru both resistors, equiv resistance is 200 ohms, then using ohms law

I = 25/200

I= .125 amps or 125 ma

__________

R= r1 * r2 / r1 +r2

R= 100 * 100 / 100 + 100

R= 10000 / 200

R= 50 ohms

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Complete Question

The accepted speed of sound at atmospheric pressure and 0 *C is 331.5 m/s. The speed of sound increases 0.607 m/s for every *C. Calculate the speed of sound at the temperature of your room(70F) and compare your measured value to the accepted value.

Answer:

[tex]V_{Tc}=344.314m/s[/tex]

Explanation:

From the question we are told that:

Speed of sound at Temperature [tex]0 \textdegree[/tex] [tex]V_0=331.5m/s[/tex]

Rate of Speed increase [tex]\triangle V_{infty}=0.607[/tex]

Generally the equation for Temperature in Celsius is mathematically given by

 [tex]Tc=\frac{100}{180}(T_f-32)[/tex]

 [tex]Tc=0.56*38[/tex]

 [tex]Tc=21.11 textdegree C[/tex]

Therefore speed at Tc

 [tex]V_{Tc}=V_0+(Tc)( V_{infty})[/tex]

 [tex]V_{Tc}=331.5+(21.11)(0.607)[/tex]

 [tex]V_{Tc}=344.314m/s[/tex]

Answer:

4210 W

Explanation:

We'll begin by calculating the energy required in lifting the water from the depth. This can be obtained as follow:

Mass (m) = 1200 Kg

Height (h) = 10 m

Acceleration due to gravity (g) = 9.8 m/s²

Energy (E₁) =?

E₁ = mgh

E₁ = 1200 × 9.8 × 10

E₁ = 117600 J

Next, we shall determine the energy required to project the water at 15 m/s. This can be obtained as follow:

Mass (m) = 1200 Kg

Velocity (v) = 15 m/s

Energy (E₂) =?

E₂ = ½mv²

E₂ = ½ × 1200 × 15²

E₂ = 600 × 225

E₂ = 135000 J

Finally, we shall determine the power of the motor. This can be obtained as follow:

Total energy (E) = E₁ + E₂

= 117600 + 135000

= 252600 J

Time (t) = 1 min = 60 s

Power (P) =?

P = E/t

P = 252600 / 60

P = 4210 W

Therefore, the power of the motor is 4210 W.

There's no multiple answers that you added if that's what you meant but it possibly could be Magma or radioactive decay of particles from the earths core if those two are any of the options

Answer:

Explanation:

We need the power equation here:

P = W/t where W is work and is defined as

W = F*displacement.

Force is a measure in Newtons, which is also weight. We have the mass of the piano, but we need to find the weight:

w = mg so

w = 166(9.8) so

w = 1600N, rounded to the correct number of sig dig. We use that now in the power equation:

[tex]4560=\frac{(1600)(15)}{t}[/tex] and isolating the unknown:

[tex]t=\frac{(1600)(15)}{4560}[/tex] so

t = 5.3 seconds