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4 years ago

The hight A note on the piano has a wavelength of 0.0487 m what’s the frequency ?

Physics

1 answer:

Brrunno [24]4 years ago

4 0

Answer:

A modern piano has 88 keys and is tuned to twelve-tone equal temperament. It has its 49th key, the fifth A, also called A4, tuned to a frequency of 440 Hz (referred to as A440).

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Natasha_Volkova [10]

Answer:

i think it might be D or C

4 0

3 years ago

What is meant by infinite slew rate

Dennis_Churaev [7]

Am infinite slew rate means that the changes in the output voltage occur immensely when the input voltage changes.
Slew rate is measurement of the response of an operational amplifier. For an ideal operational amplifier, time delay is negligible. Hence it has an infinite slew rate.
In simpler terms it means that it can provide output voltage simultaneously with the input voltage changes.

Hope this helps :)

3 0

2 years ago

Two forces whose resultant is 100N are at right angle to eachother. if one of them makes an angle of 30° with the resultant, det

mihalych1998 [28]

Let F₁ and F₂ denote the two forces, and R the resultant force.

F₁ and F₂ point perpendicularly to one another, so their dot product is

F₁ • F₂ = 0

We're given that one of these vectors, say F₁, makes an angle with R of 30°, so that

F₁ • R = ||F₁|| ||R|| cos(30°)

But we also have

F₁ • R = F₁ • (F₁ + F₂) = (F₁ • F₁) + (F₁ • F₂) = F₁ • F₁ = ||F₁||²

So, knowing that ||R|| = 100 N, we get that

(100 N) ||F₁|| cos(30°) = ||F₁||²

(100 N) cos(30°) = ||F₁||

||F₁|| ≈ 86.6 N

(And the same would be true for F₂.)

8 0

3 years ago

What does the band of stability for atomic nuclei refer to

Irina18 [472]

Explanation:

Band of stability for atomic nuclei refer to a narrow region in the graph of number of neutrons to the number of protons for stable nuclei. It is the band of nuclei stability.

We know that radioactive elements achieve stability be ejecting nucleons( neutrons and protons). The regions( combination of number of neutrons and protons) in which the nucleus is most is called band of stability.

5 0

3 years ago

EMF. Currents in dc transmission lines can be 100 A or more. Some people have expressed concern that the electromagnetic fields

mrs_skeptik [129]

Answer:

The magnetic field B of the transmission line is 4.5·10^(-6)T. The ratio B/Be is 0.0009% (there is no risk to human health)

Explanation:

we will consider a dc transmission line as an infinite longitudinal line in the Z-axis with a dc current of 180 A. To solve the problem we will use ampere's law. We can consider the geometry of the problem (Rotational symmetry in respect of Z-axis) than the field B is annular with center in the transmission line.

$\vec{B}(r,\varphi,z)=B(r)\vec{\varphi}$

$\displaystyle\oint_{C} \vec{B}(r)\,\vec{dl}=\mu I_c$

We will use a circular amperian curve C. Therefore:

$\displaystyle\oint_{C} \vec{B}(r)\,\vec{dl}=\int_{0}^{2\pi} B(r)\vec{\varphi}\,\vec{\varphi}rd\varphi=B(r)r\int_{0}^{2\pi} \,d\varphi=B(r)r2\pi=\mu I_c$

$B(r)=\displaystyle\frac{\mu 180A}{r2\pi}$

For a height of 8.0m (r=8m):

$B(8m)=\displaystyle\frac{\mu 180A}{8m2\pi}=4.5\cdot10^{-6}T$

Compared to the earth magnetic field:

$\displaystyle\frac{B}{B_e}\%= \frac{B}{B_e}100=0.0009\%$

6 0

3 years ago