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2 years ago

A neutral atom of uranium (U) has 146 neutrons and a mass number of 238. How many protons does it have?

Physics

2 answers:

loris [4]2 years ago

6 0

Answer:

Explanation:

One

I've never heard of a mass defect before you asked this question. Interesting concept.

Givens

Number of neutrons =207 - 82 = 125

Number of protons = 82

The amu of a proton is 1.00728

The amu of a neutron is 1.00866

Solution

Find out the actual mass of the Lead atom

Actual mass = 82*1.00728 + 125*1.00866

Actual mass = 208.67946

The mass defect = 208.67946 - 207 = 1.67946

That is the proper way to calculate mass defect.

Apparently the way you are supposed to do it is

Mass defect = 208.67946 - 206.975897= 1.703563 which means that C is the closest answer. You will have to look at your notes to see if amu for protons and neutrons are what I used.

Two

The number of protons is the number of Uranium on the periodic table.

92 protons. 92 comes from the position on the periodic table.

You can get the same thing by Taking its relative mass (238) and subtracting the neutrons (146) which is 238 - 146 = 92

BARSIC [14]2 years ago

4 0

Answer:

92 protons

Explanation:

The mass number is 238 , so the nucleus has <u>238 particles</u> in total, including <u>146 neutrons</u>. So to calculate the number of neutrons we have to subtract: 238 − 146 = 92

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An insect 5.00 mm tall is placed 20.0 cm to the left of a thin planoconvex lens. The left surface of this lens is flat, the righ

jenyasd209 [6]

Answer:

a) i = -9.63 cm , h ’= .0.24075 cm erect

b) i = 259.74 cm ,

Explanation:

For this exercise let's start by finding the focal length of the lens

1 / f = (n-1) (1 / R₁ - 1 / R₂)

1 / f = (1.70 -1)) 1 / ∞ - 1/13)

1 / f = 0.0538

f = - 18.57 cm

Now we can use the constructor equation

1 / f = 1 / o + 1 / i

1 / i = 1 / f - 1 / o

1 / i = -1 / 18.57 -1/20

1 / i = -0.1038 cm

I = -9.63 cm

For the height of the

image let's use magnification

m = h '/ h = - i / o

h ’= -h i / o

h ’= - 0.5 (-9.63) / 20

h ’= .0.24075 cm

b) we invert the lens

The focal length is

1 / f = (1.70 -1) (1/13 - 1 / int)

1 / f = 0.0538

f = 18.57 cm

1 / i = 1 / f -1 / o

1 / I = 1 / 18.57 - 1/20

1 / I = 3.85 10-3

i = 259.74 cm

h ’= - 0.5 259.74 / 20

h ’= 6.4935 cm

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2 years ago

Volcanoes that have fast flowing liquid lava will be narrow like a river

vodomira [7]

Answer:

Shield volcanoes, the third type of volcano, are built almost entirely of fluid lava flows. Flow after flow pours out in all directions from a central summit vent, or group of vents, building a broad, gently sloping cone of flat, domical shape, with a profile much like that of a warrior's shield.

Explanation:

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2 years ago

g a horizontal wheel of radius is rotating about a vertical axis. What is the magnitude of the resultant acceleration of a bug t

mihalych1998 [28]

Answer:

a = w² r

Explanation:

In this exercise, indicate that the wheel has angular velocity w, the worm experiences the same angular velocity if it does not move, and has an acceleration towards the center of the circle, according to Newton's second law, called the centripetal acceleration.

a = v² / r

angular and linear variables are related

v = w r

we substitute

a = w² r

where r is the radius of the wheel

4 0

2 years ago

A car accelerates from rest, and travels 400 m in 3.5 seconds. If

zheka24 [161]

Answer:

A car accelerates from rest, and travels 400 m in 3.5 seconds. If

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shd dhd bdvd dhdbduhdbdhdbbdceudd f

3 0

2 years ago

HELP PLEASE 20 POINTS SHOW WORK, ALL EQUATIONS

nataly862011 [7]

Answer:

s = 3 m

Explanation:

Let t be the time the accelerating car starts.

Let's assume the vehicles are point masses so that "passing" takes no time.

the position of the constant velocity and accelerating vehicles are

s = vt = 40(t + 2) cm

s = ½at² = ½(20)(t)² cm

they pass when their distance is the same

½(20)(t)² = 40(t + 2)

10t² = 40t + 80

0 = 10t² - 40t - 80

0 = t² - 4t - 8

t = (4±√(4² - 4(1)(-8))) / 2(1)

t = (4± 6.928) / 2 ignore the negative time as it has not occurred yet.

t = 5.464 s

s = 40(5.464 + 2) = 298.564 cm

300 cm when rounded to the single significant digit of the question numerals.

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2 years ago