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3 years ago

15

An amplifier has a 50 watt output and a 5 watt input. what is the gain in decibels for this amplifier, rounded to the nearest de

cibel?

1 answer:

Marrrta [24]3 years ago

6 0

Gain in decibels is given by;

Gain db = 10*log (Po/Pi), where Po = Power output, Pin = Power input

Substituting;

Gain in db = 10 * log (50/5) = 10 db

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An open-end mercury manometer is connected to a low-pressure pipeline that supplies a gas to a laboratory. Because paint was spi

Svetllana [295]

Answer:

a

$P_G = 14.03 \ psig$

b

$h_m = 0.148 \ m$

Explanation:

From the question we are told that

The pressure of the manometer when there is no gas flow is $P_{m} = 15.5 \ psig = 15.5 * 6894.76 = 106868.78 \ N/m^2$

The level of mercury is $h = 950 \ mm = 0.950 \ m$

The drop in the mercury level at the visible arm is $d = 39.0 = 0.039 \ m$

Generally when there is no gas flow the pressure of the manometer is equal to the gauge pressure which is mathematically represented as

$P_g = P_m = g * \delta h * \rho$

Here $\rho$ is the density of mercury with value $\rho = 13.6 *10^{3} kg/m^3$

and $\delta h$ is the difference in the level of gas in arm one and two

So

$\delta h = \frac{106868.78}{ 13.6 *10^{3} * 9.8 }$

$\delta h = 0.802 \ m$

Generally the height of the mercury at the arm connected to the pipe is mathematically represented as

$h_m = 0.950 - 0.802$

=> $h_m = 0.148 \ m$

Generally from manometry principle we have that

$P_G + \rho * g * d - \rho * g * [h - (h_m + d)] = 0$

Here $P_G$ is the pressure of the gas

$P_G +13.6 *10^{3} * 9.8 * 0.039 - 13.6 *10^{3} * 9.8 * [0.950 - (0.148 + 0.039)] = 0$

$P_G = 9.6724 04 *10^{4} \ N/m^2$

converting to psig

$P_G = \frac{ 9.6724 04 *10^{4} }{6894.76}$

$P_G = 14.03 \ psig$

6 0

3 years ago

When point charges q = +8.4 uC and q2 = +5.6 uC are brought near each other, each experiences a repulsive force of magnitude 0.6

Bezzdna [24]

Answer:

Distance between the charges, r = 0.8 meters

Explanation:

Given that,

Charge 1, $q_1=+8.4\ \mu C=+8.4\times 10^{-6}\ C$

Charge 2, $q_2=+5.6\ \mu C=+5.6\times 10^{-6}\ C$

Repulsive force between charges, F = 0.66 N

Let r is the distance between charges. The formula for the electrostatic force is given by :

$F=k\dfrac{q_1q_2}{r^2}$

$r=\sqrt{\dfrac{kq_1q_2}{F}}$

$r=\sqrt{\dfrac{9\times 10^9\times 8.4\times 10^{-6}\times 5.6\times 10^{-6}}{0.66}}$

r = 0.8009 meters

or

r = 0.8 meters

So, the distance between the charges i 0.8 meters. Hence, this is the required solution.

4 0

3 years ago

An arrow is projected by a bow vertically up with a velocity of 40 m/s, and reaches a target in 3 s. What is the velocity of the

Fittoniya [83]

Answer:

Explanation:

Step one:

given data

initial velocity u= 40m/s

time taken t=3seconds

final velocity v=?

Step two:

applying the first equation of motion

v=u-gt--- (the -ve sign implies that the arrow is against gravity)

assume g=9.81m/s^2

v=40-9.81*3

v=40-29.43

v=10.57m/s

Step three:

how high the target is located

applying

s=ut-1/2gt^2

s=40*3-1/2(9.81)*3^2

s=120-88.29/2

s=120-44.145

s=75.86m

6 0

3 years ago

Explain at least two differences between justice system laws and scientific laws.

bezimeni [28]

The adversarial system is rigid – the roles are proscribed – the prosecutor wants to convict, the defendant wants a decision of not guilty. They are not just allowed but expected to bias their presentation, trusting the truth to come out between the adversaries. Science certainly has its sides of partisanship and bias. But these sides are self-imposed and can be abandoned at any time. While a prosecutor should not lie or hide evidence, and should drop a case if they become convinced the defendant is innocent, they wake up in the morning with no choice about which side of the argument they will come down on. In the criminal justice system the advocates are rigidly fixed in their roles and the jurors are rigidly neutral (the process to find a random neutral jury took as long as the trial itself). In science, the advocates are the same people as the jurors. And as a result they have to be willing to be flexible and change their minds. A good scientist shouldn’t have a pre-determined rigid answer to a question.
Lack of investigation – we jurors were told over and over not to investigate the situation ourselves. We were to make our decision only on the basis of the evidence presented to us. I can tell you in the case I was on there were at least two whopping big questions hanging over the case that nearly every juror in the room identified as very important but not addressed by either lawyer. Either one of them (whether the defendant’s schedule allowed time to drink before being stopped in the car, whether a particular medical condition could affect breathalyzer tests) could have changed the outcome. We could have answered one of these with 10 minutes on google and the other with some very simple subpoena of records. But we couldn’t use any of this. Scientists obviously are the opposite – if they need more information, they are expected to go get it before making an opinion.
Reliance on personal testimony – although science and trials share a focus on evidence, trials recognize testimony of individual people under oath as a major form of evidence. They certainly acknowledge the possibility of lying and explicitly instruct jurors to decide what testimony they believe. My case was unusual in that there was so much video footage, but still a majority of the case came down to testimony by the police officers, and most cases even a few years ago would have had only testimony. Science on the other hand, doesn’t accept testimony. Or does it? What else is the methods and results section of a paper? I’m on the fence whether science is so different on this one.

3 0

3 years ago

Which of the following does not affect the rate of solubility

lions [1.4K]

Answer:

Weight

Explanation:

Weight does not have any effect on solutbility.

For gases their solubility relies a lot on pressure exerted. At higher presure, gases dissolves more readily than ever. The relationship between solubility and pressure is a direct one.

Higher surface area facilitates the rate of a reaction and in essence, helps to dissolve more solute. Surface area exposes a solute to the action of more solvent which would aid solutbility.

Temperature has a high effect on solubility. An increase in temperature would make more solute dissolve in it.

3 0

3 years ago

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