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3 years ago

The spread of fire from the ground floor to an upper floor of a building primarily due to heat transfer by

1 answer:

4 0

The correct answer is by convection.

In fact, in a fluid (like the air in the room full of fire) the warmer parts of the fluid move upward, replacing the colder parts which go down. For this very same reason, the fire spreads moving toward the upper floors of the bulding.

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Nichrome wire, often used for heating elements, has resistivity of 1.0 × 10-6 Ω ∙ m at room temperature. What length of No. 30 w

worty [1.4K]

Answer:

Length = 2.453 m

Explanation:

Given:

Resistivity of the wire (ρ) = 1 × 10⁻⁶ Ω-m

Diameter of the wire (d) = 0.250 mm = 0.250 × 10⁻³ m

Resistance of the wire (R) = 50 Ω

Length of the wire (L) = ?

The area of cross section is given as:

$A=\frac{1}{4}\pi d^2\\\\A=\frac{1}{4}\times\ 3.14\times (0.250\times 10^{-3})^2\\\\A=0.785\times 6.25\times 10^{-8}\\\\A=4.906\times 10^{-8}\ m^2$

We know that, for a constant temperature, the resistance of a wire is directly proportional to its length and inversely proportional to its area of cross section. The constant of proportionality is called the resistivity of the wire. Therefore,

$R=\rho \frac{L}{A}$

Expressing the above in terms of length 'L', we get:

$L=\frac{RA}{\rho}$

Plug in the given values and solve for 'L'. This gives,

$L=\frac{50\times 4.906\times 10^{-8}}{1\times 10^{-6}}\ m\\\\L=\frac{2.453}{1}=2.453\ m$

Therefore, length of No. 30 wire (of diameter 0.250 mm) is 2.453 m.

4 0

3 years ago

A certain AM radio wave has a frequency of 24Hz. Given that radio waves travel at 3 m/s, what is the wavelength of this radio wa

Dahasolnce [82]

Answer:

Wavelength of AM radio wave = 0.125 meter

Explanation:

Given:

Frequency of AM radio wave = 24 Hz

Velocity of AM radio wave = 3 m/s

Find:

Wavelength of AM radio wave

Computation:

Wavelength = Velocity / Frequency

Wavelength of AM radio wave = Velocity of AM radio wave / Frequency of AM radio wave

Wavelength of AM radio wave = 3 / 24

Wavelength of AM radio wave = 0.125 meter

3 0

2 years ago

is it possible that the philippines can solely rely from geothermal energy? state your opinion why or why not?

andriy [413]

Answer:

It is possible that the Philippines depends exclusively on geothermal energy.

Explanation:

The Philippines is located in the Pacific circle of fire, which allows this country to be a region with a large number of villagers and with great seismic activity, which makes the Philippines a region with great potential for geothermal energy. This is possible thanks to the great underground heat that the region presents, making it able to depend entirely on geothermal energy, if investments and technology capable of boosting this energy sector have been stimulated.

6 0

2 years ago

The sun generates both mechanical and electromagnetic waves. Which statement about those waves is true?

Vladimir [108]

Answer: The correct answer for this question is letter (B) The electromagnetic waves reach Earth, while the mechanical waves do not. The sun generates both mechanical and electromagnetic waves. Space, between the sun and the earth is a nearly vacuum. So mechanical wave can not spread out in the vacuum.

Hope this helps!

4 0

3 years ago

50 points According to kinetic theory, in a closed system, what happens when two atoms collide?

vfiekz [6]

I believe its the 1st option

8 0

3 years ago

Read 2 more answers