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3 years ago

Which of the following statements is true?

Physics

2 answers:

Tanya [424]3 years ago

7 0

the third choice is the answer

hram777 [196]3 years ago

4 0

All the radiation from stars is the result of nuclear fusion in their cores.

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Calculate the orbital speed (in m/s) of a satellite that circles the Earth with a time period of 12.00 hours. The mass of the Ea

Hoochie [10]

Answer:

$v = 3869 m/s$

Explanation:

As we know that the orbital speed of the satellite is given as

$v = \sqrt{\frac{GM}{r}}$

also we know that

time period of the revolution is given as

$T = \frac{2\pi r}{v}$

now from above equation we know that

$T = \frac{2\pi (\frac{GM}{v^2})}{v}$

$T = \frac{2\pi GM}{v^3}$

so we will have

$v = (\frac{2\pi GM}{T})^{1/3}$

now plug in all data in this equation

$v = (\frac{2\pi (6.67 \times 10^{-11})(5.97 \times 10^{24})}{12 \times 3600})^{1/3}$

$v = 3869 m/s$

3 0

3 years ago

The visible spectrum refers to the portion of the electromagnetic spectrum that we ________.

yKpoI14uk [10]

<h2>Answer: can see</h2>

Explanation:

The portion visible by the human eye of the electromagnetic spectrum is between 380 nm (violet-blue) and 780 nm (red) approximately. Which means this part of the spectrum is located between ultraviolet light and infrared light.

Note the fact only part of the whole electromagnetic spectrum is visible to humans is because the receptors in our eyes are only sensitive to these wavelengths.

Therefore:

<h2>The visible spectrum refers to the portion of the electromagnetic spectrum that <u>we </u><u>can see</u></h2>

8 0

3 years ago

Which of the following is equivalent to 2.5 meters

blsea [12.9K]

B is the correct answer for sure bro

5 0

3 years ago

Read 2 more answers

A common flashlight bulb is rated at 0.32 A and 4.3 V (the values of the current and voltage under operating conditions). If the

sleet_krkn [62]

Answer:

1176.01 °C

Explanation:

Using Ohm's law,

V = IR................. Equation 1

Where V = Voltage, I = current, R = Resistance when the bulb is on

make R the subject of the equation

R = V/I.................. Equation 2

R = 4.3/0.32

R = 13.4375 Ω

Using

R = R'(1+αΔθ)............................. Equation 3

Where R' = Resistance of the bulb at 20°, α = Temperature coefficient of resistivity, Δθ = change in temperature

make Δθ the subject of the equation

Δθ = (R-R')/αR'.................. Equation 4

Given: R = 13.4375 Ω, R' = 1.6 Ω, α = 6.4×10⁻³ K⁻¹

Substitute into equation 4

Δθ = (13.4375-1.6)/(1.6×0.0064)

Δθ = 11.8375/0.01024

Δθ = 1156.01 °C

But,

Δθ = T₂-T₁

T₂ = T₁+Δθ

Where T₂ and T₁ = Final and initial temperature respectively.

T₂ = 20+1156.01

T₂ = 1176.01 °C

5 0

3 years ago

Read 2 more answers

A 50-kg copper block initially at 140°C is dropped into an insulated tank that contains 90 L of water at 10°C. Determine the fin

Kaylis [27]

Answer:

16.33°C

Explanation:

Applying,

Heat lost by copper = heat gained by water

cm(t₁-t₃) = c'm'(t₃-t₂).............. Equation 1

Where c = specific heat capacity of copper, m = mass of copper, c' = specific heat capacity of water, m' = mass of water, t₁ = initial temperature of copper, t₂ = initial temperature of water, t₃ = final equilibrium temperature.

From the question,

Given: m = 50 kg, t₁ = 140°C, m' = 90 L = 90 kg, t₂ = 10°C

Constant: c = 385 J/kg°C, c' = 4200J/kg°C

Substitute these values into equation 1

50(385)(140-t₃) = 90(4200)(t₃-10)

(140-t₃) = 378000(t₃-10)/19250

(140-t₃) = 19.64(t₃-10)

140-t₃ = 19.64t₃-196.6

19.64t₃+t₃ = 196.4+140

20.64t₃ = 336,4

t₃ = 336.4/20.6

t₃ = 16.33°C

7 0

3 years ago