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3 years ago

Are There some sounds for which we are all deaf

1 answer:

6 0

Answer: Infrasound is the span of low-frequency sounds below 20 Hz that fall below the hearing range of humans. While these sounds escape our ears, scientific instruments can detect them—and tell us some interesting things about the planet.

Explanation:

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Two astronauts are 2.00 m apart in their spaceship. One speaks to the other. The conversation is transmitted to earth via electr

Eduardwww [97]

Answer:

$D=1693742.7m$

Explanation:

For sound waves we have v=d/t where v is the speed of sound and d the distance between the astronauts, while for electromagnetic waves we have c=D/t where c is the speed of light and D the distance between the spaceship and Earth. <em>We have written both times as the same</em> because is what is imposed by the problem, so we have t=d/v=D/c, which means:

$D=\frac{dc}{v}$

And for our values:

$D=\frac{(2m)(299792458m/s)}{354m/s}=1693742.7m$

5 0

2 years ago

Singly charged gas ions are accelerated from rest through a voltage of 10.3 V. At what temperature (in K) will the average kinet

Natasha_Volkova [10]

Answer:

Temperature of the gas molecules is 7.96 x 10⁴ K

Explanation:

Given :

Ions accelerated through voltage, V = 10.3 volts

The work done to change the position of singly charged gas ions is given by the relation :

W = q x V

Here q is charge of the ions and its value is 1.6 x 10⁻¹⁹ C.

Average kinetic energy of gas molecules is given by the relation:

K.E. = $\frac{3}{2}kT$

Here T is temperature and k is Boltzmann constant and its value is 1.38 x 10⁻²³ J/K.

According to the problem, the average kinetic energy of gas is equal to the work done to move the singly charged ions, i.e. ,

K.E. = W

$\frac{3}{2}kT = qV$

Rearrange the above equation in terms of T :

$T= \frac{2qV}{3k}$

Substitute the suitable values in the above equation.

$T=\frac{2\times1.6\times10^{-19}\times10.3 }{3\times1.38\times10^{-23} }$

T = 7.96 x 10⁴ K

5 0

3 years ago

Based on The MOHS hardness Scale, which mineral could be scratched by a penny but not by a fingernail

melomori [17]

The correct answer is B. Calcite

Explanation:

Mohs hardness scale indicates the hardness of minerals using a scale from 1 to 10 as well as defining the objects or tools that can be used to scratch the minerals. These two features of minerals are shown in the table of the image. About this, it is shown gypsum and talc can be scratched by just a fingernail, considering minerals with a hardness of 2.5 or below can be scratched by a fingernail. In the case of calcite that has a hardness of 3, this cannot be scratched by a fingernail, but it can be scratched by a penny, which works for minerals with a hardness of 3.5 or below. Thus, the correct answer is Calcite.

6 0

2 years ago

The Z0 boson, discovered in 1985, is the mediator of the weak nuclear force, and it typically decays very quickly. Its average r

Dvinal [7]

Answer:

The lifetime of the particle is $\Delta t = 2.6*10^{-25} \ s$

Explanation:

From the question we are told that

The average rest energy is $E = 91.19 \ GeV = 91.19GeV * \frac{1.60 *10^{-10} J }{1GeV} = 1.46 *10^{-8}J$

The intrinsic width is $\Delta E =2.5eV = 2.5GeV * \frac{1.60 *10^{-10}J }{1GeV} = 4*10^{-10} J$

The lifetime is mathematically represented as

$\Delta t = \frac{h}{\Delta E}$

Where h is the Planck's constant with a value of $1.055*10^{-34} \ J\cdot s$

substituting values

$\Delta t = \frac{1.055*10^{-34}}{4 *10^{-10}}$

$\Delta t = 2.6*10^{-25} \ s$

6 0

2 years ago

what effect would you expect the termperature of a material to have on the ease with which electrons can be ejected from it via

Ilya [14]

Answer:

The photoelectric effect is a phenomenon in which the photoelectrons are emitted from the metal when an incident electromagnetic wave hits the metal. The incident light should have a threshold frequency to meet the work function of the metal

8 0

1 year ago