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3 years ago

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If 1.8 1016 electrons enter a light bulb in 3 milliseconds, what is the magnitude of the electron current at that point in the c

ircuit?

1 answer:

Mice21 [21]3 years ago

7 0

Answer:

I = 0.96 A

Explanation:

No of electrons, $n=1.8\times 10^{16}$

Time, t = 3 ms = $3\times 10^{-3}\ s$

We need to find the electric current. We know that electric charge per unit time is equal to the electric current.

$I=\dfrac{q}{t}$

q = ne (Quantization of electric charge)

$I=\dfrac{ne}{t}\\\\I=\dfrac{1.8\times 10^{16}\times 1.6\times 10^{-19}}{3\times 10^{-3}}\\\\I=0.96\ A$

So, the electric current is 0.96 A.

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You are standing in a building whose height (40m) you throw a ball downward at a angle of -30 at a speed of (10m/s) acceleration

jeyben [28]

Answer: 3.41 s

Explanation:

Assuming the question is to find the time $t$ the ball is in air, we can use the following equation:

$y=y_{o}+V_{o}sin \theta t-\frac{1}{2}gt^{2}$

Where:

$y=0m$ is the final height of the ball

$y_{o}=40 m$ is the initial height of the ball

$V_{o}=10 m/s$ is the initial velocity of the ball

$t$ is the time the ball is in air

$g=9.8 m/s^{2}$ is the acceleration due to gravity

$\theta=30\°$

Then:

$0 m=40 m+(10 m/s)(sin(30\°))t-\frac{1}{2}9.8 m/s^{2}t^{2}$

$0 m=40 m+5m/s t-4.9 m/s^{2}t^{2}$

Multiplying both sides of the equation by -1 and rearranging:

$4.9 m/s^{2}t^{2}-5m/s t-40 m=0$

At this point we have a quadratic equation of the form $at^{2}+bt+c=0$ , which can be solved with the following formula:

$t=\frac{-b \pm \sqrt{b^{2}-4ac}}{2a}$

Where:

$a=4.9$

$b=-5$

$c=-40$

Substituting the known values:

$t=\frac{-(-5) \pm \sqrt{(-5)^{2}-4(4.9)(-40)}}{2(4.9)}$

Solving the equation and choosing the positive result we have:

$t=3.41 s$ This is the time the ball is in air

5 0

3 years ago

Which part of the brain serves to regulate the endocrine system?

Debora [2.8K]

Answer:

hypothalamus

Explanation:

The hypothalamus is known as the master switchboard because it's the part of the brain that controls the endocrine system. The pituitary gland, which hangs by a thin stalk from the hypothalamus, is called the master gland of the body because it regulates the activity of the endocrine glands.

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3 years ago

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A cellphone charger has a transformer with 2000 turns in the primary coil which converts 240v a.c to 6v a.c and a rectifier that

inn [45]

Answer:

As we are converting 220V AC into a 5V DC, first we need a step-down transformer to reduce such high voltage. Here we have used 9-0-9 1A step-down transformer, which convert 220V AC to 9V AC. In transformer there are primary and secondary coils which step up or step down the voltage according to the no of turn in the coils.

Selection of proper transformer is very important. Current rating depends upon the Current requirement of Load circuit (circuit which will use the generate DC). The voltage rating should be more than the required voltage. Means if we need 5V DC, transformer should at least have a rating of 7V, because voltage regulator IC 7805 at least need 2V more i.e. 7V to provide a 5V voltage.

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2 years ago

A laptop can convert 400J of electrical energy into a 240J of light and sound. What is the efficiency? Where does the rest of th

Blababa [14]

Efficiency = (Wanted) energy out ÷ energy in × 100

Energy in = 400J
Wanted Energy out = 240J

Energy cannot be used up, only transferred, so the remaining energy is most likely to be transferred into unwanted energy (loss of energy) such as heat energy.

Efficiency = 240 ÷ 400 × 100
Efficiency = 0.6 × 100
Efficiency = 60%

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3 years ago

EASY MATCHING PLEASE HELP!

kakasveta [241]

<h2><u>Answers:</u></h2><h2>1.) Right answer: polarization </h2>

Alignment of light in only one vibrational orientation: polarization

Normally, electromagnetic waves (light) are not polarized, so electromagnetic vibration occurs in all planes. But when we get these waves to vibrate in a single plane, we have polarized light.

This is possible because electromagnetic waves are transversal waves, this means the electric field oscillates in all normal directions to the direction of wave propagation.

In other words:

<em>Its oscillation occurs in the transversal direction to its propagation. </em>

So, when polarization occurs the electric field vibrates or oscillates in a given plane, called the <u>polarization plane</u>.

It should be noted that this phenomenon is only possible in transversal waves, in longitudinal waves, such as sound waves, polarization is not possible because its oscillation occurs in the same direction as its propagation.

<h2>2.) Right answer: concave </h2>

Mirror that causes parallel incident rays of light to converge at the focus: concave

A concave mirror, or convergent mirror, has a reflective surface that is curved inwards.

The concave mirrors reflect the light making it converge in a focal point therefore they are used to focus the light. This occurs because the light is reflected with different angles, since the normal to the surface varies from one point to another of the mirror.

<h2>3.) Right answer: photoelectric effect </h2>

phenomenon that can be explained only by a particle model for light: photoelectric effect

Light can be considered as a wave or as particles (photons), in this context the photoelectric effect can only be explained based on the corpuscular model (particles) of light.

Then, the photoelectric effect consists of the emission of electrons (electric current) that occurs when light falls on a metal surface under certain conditions.

If the light is a stream of photons and each of them has energy, this energy is be able to pull an electron out of the crystalline lattice of the metal and communicate, in addition, a kinetic energy.

<h2>4.) Right answer: Taylor's experiment </h2>

experiment that showed that diffraction effects could be attributed to light particles: Taylor's experiment

This experiment was carried out by Geoffrey Taylor in 1909 with a flame as a light source, a diffraction grating and a photographic plate.

All this to test the diffraction of light.

<h2> 5.) Right answer: reflection </h2>

principal use of mirrors: reflection

Mirrors fulfill the principle of reflection, which occurs when the light rays fall on a very flat reflecting surface are reflected so that the incident angle is equal to the reflected angle

<h2>6.) Right answer: mirage </h2>

image of the sky seen on a hot road: mirage

A mirage is the product of an optical illusion due to the total reflection of the light when crossing layers of hot air of different density; this causes the perception of the inverted image of distant objects, as if they were reflected in the water.

<h2>7.) Right answer: virtual </h2>

type of images always produced by convex mirrors: virtual

In the convex mirrors the focus is virtual and the focal distance is negative. This is how the reflected rays diverge and only their extensions are cut at a point on the main axis, resulting in a virtual image of the real object.

<h2>8.) Right answer: diffraction </h2>

pattern produced by light through a narrow slit: diffraction

Diffraction is a phenomenon that is based on the deviation of the waves (light waves in this case) when encountering an obstacle or going through a slit

<h2>9.) Right answer: convex </h2>

shape of a converging lens: convex

A convex lens is thicker in the center than at its edges and concentrates (converges) at a point the rays of light that pass through it.

<h2>10.) Right answer: dispersion </h2>

separating light into component colors: dispersion

The dispersion of light occurs when a beam of composite light is refracted (the different rays of light are diverted depending on their frequencies) in some medium, leaving their constituent colors separated.

The best known case is when a beam of white light from the sun passes through a prism, thus obtaining rays of different colors like those of the rainbow.

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3 years ago

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