Practice: How many electrons make up −1.5 × 10^{−5} 𝐶?

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Electric Charge | 15 mins | 0 completed | Learn |

Charging Objects | 7 mins | 0 completed | Learn |

Charging By Induction | 4 mins | 0 completed | Learn |

Conservation of Charge | 6 mins | 0 completed | Learn |

Coulomb's Law (Electric Force) | 48 mins | 0 completed | Learn Summary |

Electric Field | 40 mins | 0 completed | Learn Summary |

Electric Fields in Capacitors | 14 mins | 0 completed | Learn |

Electric Field Lines | 17 mins | 0 completed | Learn |

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Gauss' Law | 31 mins | 0 completed | Learn Summary |

Practice: How many electrons make up −1.5 × 10^{−5} 𝐶?

Example #2: Electrons In Water (Using Density)

This charge is negative, since the total charge is made up of a bunch of electrons.

**Transcript**

Hey guys, let's do another example about electric charge, okay? Water weighs one kilogram per liter has a molecular weight of 18 grams per mole and has 10 electrons per molecule.

Part A how many electrons does two liters of water have? An Part B, what charges, what charge do these electrons represent? So, how many electrons do we find in Part A? what is the charge of those electrons, okay? So, for Part A. First, what we want to do is we want to figure out how to get from liters which is what we're given, we're given two liters of water to number of electrons, this will tell us how to solve the problem, we need to create a sort of map to the solution, okay? Let's start with liters, right? Because that's what's given to us, what can we go to next? Well, we're told that there's a conversion between kilograms and liters that we can say for every liter of water it has a mass of one kilogram. So, we know how to go from liters to kilograms, next we have grams to moles. Now, we don't have kilograms to moles but we know right away that one kilogram is 1,000 grams. So, we can easily go from kilograms to grams and then using the conversion go from grams to moles. Now, our last conversion is electrons per molecule, we don't have our number of molecules yet, we have in moles but we can use Avogadro's number to convert moles to molecules. Now, using our last conversion factor, we can go from molecules to number of electrons. So, this right here is our map, that's going to guide us through this problem, okay? So, let's start doing these conversions, 2 liters of water times 1 kilogram per liter is 2 kilograms. So, our water has a mass of 2 kilograms now right away, we know that that's equivalent to 2,000 grams, okay? So, we've done this step and this step. Now, we need to go from grams to moles, okay? 2,000 grams times 18 grams per one mole is about 111 moles. So, we've done the next step. Now, we need to go from moles to molecules using Avogadro's number 111 moles times 1 mole per 6 times 10 to the 23 molecules is 6. Seven times 10 to the 25 molecules of water, okay? So, we've done this step, the last step is simply to figure out how many electrons are represented by this much water as many molecules of water, we know that it's 10 electrons per molecule. So, it's very simple, we just multiply this number by 10, 6.7 times 10 to the 26 electrons, okay? And we followed our map successfully from liters which was given to us to electrons, okay? Now, part be, what charge does this amount of electrons represent? Well, each electron has a charge e, the elementary charge and we have some number of electrons in which we figured out in part A. So, multiplying these together will tell us our total charge our number is 6.7 times 10 to the 26 and the elementary charge is what? Remember, guys you need to know this 1.6 times 10 to the negative 19 coulombs multiplying those together we get a total charge of 1.07 times 10 to the eighth, cool? Okay.

Practice: How many electrons do you have to add to decrease the charge of an object by 16uC?

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What is the charge on an unknown ion which contains 250 protons, 270 neutrons, and 244 electrons?

A metal sphere is insulated electrically and is given a charge. If 50 electrons are added to the sphere in giving a charge, how many Coulombs are added to the sphere? (e= 1.6x10-19 C)
A) -50 C
B) -8.0x10-18 C
C) -8.0x10-20 C
D) -80 C

The charge on the proton is the same asA) the charge on the neutron.B) the charge on the electron.C) the charge on the atom.D) the charge on the electron, but of the opposite sign.

An object has a positive charge of 5.0 μC. What is the net number of electrons lost/gained?
A. 1.602 x 10-19 lost electrons
B. 3.12 x 1013 lost electrons
C. 5.0 x 106 lost electrons
D. 5.0 x 106 gained electrons
E. 3.12 x 1013 gained electrons

Describe the experiment, which established that atoms contain a small nucleus, which contains almost all of its mass.

An initially neutral conductor contains a hollow cavity in which there is a + 100 nCpoint charge. A charged rod transfer -50 nC to the conductor.Afterward, what is the charge:(a) on the inner wall of the cavity wall(b) on the external surface of the conductor?

Consider the following configuration of fixed, uniformly charged spheres (see the figure ):a blue sphere fixed at the origin with positive charge q,a red sphere fixed at the point (d1, 0) with unknown charge qred, anda yellow sphere fixed at the point (d2cos(θ), -d2sin(θ)) with unknown charge qyellow.a) What is the sign on the charge of the yellow sphere? Positive or Negativeb) What is the sign of the charge on the red sphere? Positive or Negativec) What is the sign of the charge on the blue sphere? Positive or Negative

To start a car engine, the car battery moves 3.75x1021 electrons through the start motor. How many coulombs of charge were moved?

During any process, the net electric charge of an isolated system does not change (is conserved).True or False

A battery-operated car utilizes a 12.0 V system. Find the charge the batteries must be able to move in order to accelerate the 750 kg car from rest to 25.0 m/s, make it climb a 2.00×102 m high hill, and then cause it to travel at a constant 25.0 m/s by exerting a 5.00×102 N force for an hour.

How to give the spheres exactly equal but opposite charges? a) Make sure spheres are not in contact with each other. Rub the glass rod on the silk to charge the rod positively (hence to charge piece of silk negatively). Bring the rod near, but not touching, one of the spheres. Do the same with piece of silk and another sphere. Remove the glass rod and the piece of silk. b) Make sure spheres are not in contact with each other. Rub the glass rod on the silk to charge the rod positively (hence to charge piece of silk negatively). Touch one of the spheres with the glass rod then touch another one with the piece of silk. c) Put the two metal spheres in contact with each other. Then rub the glass rod on the silk to charge the rod positively (hence to charge piece of silk negatively). Touch one of the spheres with the glass rod then separate the spheres. Touch another sphere with the piece of silk. d) Put the two metal spheres in contact with each other. Then rub the glass rod on the silk to charge the rod positively (hence to charge piece of silk negatively). Bring the rod near, but not touching, one of the spheres. Separate the spheres and remove the rod.

In the late 19th century, great interest was directed toward the study of electrical discharges in gases and the nature of so-called cathode rays. One remarkable series of experiments with cathode rays, conducted by J. J. Thomson around 1897, led to the discovery of the electron.With the idea that cathode rays were charged particles, Thomson used a cathode-ray tube to measure the ratio of charge to mass, q/m, of these particles, repeating the measurements with different cathode materials and different residual gases in the tube.What is the most significant conclusion that Thomson was able to draw from his measurements?(a) He found a different value of q/m for different cathode materials.(b) He found the same value of q/m for different cathode materials.(c) From measurements of q/m he was able to calculate the charge of an electron.(d) From measurements of q/m he was able to calculate the mass of an electron.

When a honeybee flies through the air, it develops a charge of +17 pC. How many electrons did it lose in the process of acquiring this charge?

How many electrons are necessary to produce 1.0 C of negative charge? (e=1.60x10-19C)

The charge carried by one electron is e = -1 6 × 10-19 C. The number of electrons necessary to produce a charge of -1.0 C isA) 6.3 × 1018 B) 1.6 × 109C) 6.3 × 109D) 1.6 × 1019E) none of the above

The charge of an electron is -1.60 × 10-19 C. Determine the charge to mass ratio of the electron (in 1011 C/kg). (Hint: divide the electron's charge by its mass; the answer is a negative number with a positive exponent)

A plastic rod is charged to -20nC by rubbing.a. Have electrons been added to the rod or protons removed? Explain.b. How many electrons have been added or protons removed?

In a typical lightning strike, 2.5 C flows from cloud to ground in 0.20 ms. What is the current during the strike?

The positive charge in (Figure 1) is +Q.What is the negative charge if the electric field at the dot is zero?

A hollow, conducting sphere with an outer radius of 0.254 m and an inner radius of 0.202 m has a uniform surface charge density of +6.63x10-6 C/m2. A charge of -0.830 μC is now introduced into the cavity inside the sphere. What is the new charge density on the outside of the sphere?

The magnitude of the charge of an electron is:a. about 1000 times the charge of a protonb. equal to the magnitude of the charge of a protonc. None of the given answers is correctd. equal to the charge of a neutron

If you place a charged object next to an uncharged object that is a conductor, A) The force depends on whether the charge is positive or negative. B) There is no force between the two objects. C) There is an attractive force between the two objects. D) There is a repulsive force between the two objects.

The electric field 5.40 cm from a very long charged wire is (2100 N/C , toward the wire).What is the charge (in nC) on a 1.00-cm-long segment of the wire?

A very large plastic sheet carries a uniform charge density of -6.00nC/m2 on one face.a) As you move away from the sheet along a line perpendicular to it, does the potential increase or decrease? How do you know, without doing any calculations?a. Increaseb. Decreasec. Stays the sameb) Find the spacing between equipotential surfaces that differ from each other by 1.00 V

The Stanford Linear Accelerator Center (SLAC) operated on electron storage ring about 72.0 m in diameter called SPEAR (closed in 2009), in which a circulating beam of electrons moved at nearly the spend of light.Assuming that this electron beam had a current of I7 A, how many electrons were in the beam at any given movement?

If two objects are electrically attracted to each other, A) both objects must be negatively charged. B) both objects must be positively charged. C) one object must be negatively charged and the other object must be positively charged. D) the objects could be electrically neutral. E) None of the above statements are absolutely true.

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