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3 years ago

If the atomic radius of lead is 0.175 nm, calculate the volume of its unit cell in cubic meters.

1 answer:

5 0

Before any calculations, we need to determine first the crystal structure of the lead metal. From literature, the lead metal assumes an FCC structure. So, it would have 4 atoms per units cell where the three atoms is the sum of all the portion of an atoms in each face of the cell and the 1 atom is the sum of all the portion of the corner atoms. The volume of the unit cell is equal to the edge length raise to the power three or V = a^3. The edge length can be calculated from the radius of the atoms by the pythagorean theorem. We do as follows:

V = a^3
a^2 + a^2 = (4r)^2
2a^2 = (4r)^2
a = 2r
V = (2r)^3
V = 16r^3
V = 16 (0.175x10^-9)^3
V = 1.21 x 10^-28 m^3

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A certain fm radio station broadcasts electromagnetic waves at a frequency of 125000 hertz. these radio waves travel at a speed

faltersainse [42]

Speed = frequency x wavelength
300,000,000 = 125000 x wavelength
wavelength = 125000/300,000,000 =4.16667x10^-4 meters
or 4.1667E-4 meters

4 0

3 years ago

An object of height 2.7 cm is placed 29 cm in front of a diverging lens of focal length 16 cm. Behind the diverging lens, and 12

kati45 [8]

Answer:

A) q = -8.488 cm , B) m = 0.29

Explanation:

A) For this exercise in geometric optics, we will use the equation of the constructor

$\frac{1}{f} = \frac{1}{p} + \frac{1}{q}$

where p and q are the distance to the object and image, respectively and f is the focal length

in our case the distance the object is p = 29 cm the focal length of a diverging lens is negative and indicates that it is f = - 12 cm

$\frac{1}{q} = \frac{1}{f} - \frac{1}{p}$

we calculate

$\frac{1}{q} = - \frac{1}{12} - \frac{1}{29}$

$\frac{1}{q}$ = - 0.1178

q = -8.488 cm

the negative sign indicates that the image is virtual

B) the magnification is given

$m = \frac{h'}{h} = - \frac{q}{p}$

we substitute

m = $- \frac{-8.488}{29}$

m = 0.29

the positive sign indicates that the image is right

4 0

3 years ago

A neutron star that spins and emits beams of energy is called a _____.

salantis [7]

Pulsar or also sometimes as a actively rotating accretion disc

5 0

3 years ago

PLEASE HELP! DUE DATE IS TODAY

g100num [7]

Answer:

Question 2

Part (a)

Chlorine: type of compound = chloride

Oxygen: type of compound = oxide

Part (b)

The iron reacts with water and oxygen to form rust.

A water molecule is made up of two hydrogen atoms joined to one oxygen atom: Di-hydrogen oxide.

Question 3

This circuit is in parallel.

The current in a parallel circuit splits into different branches then combines again before it goes back into the supply.

We are told that A₁ = 0.8 A

As the lamps have equal resistance, the current splits equally:

A₂ = 0.4 A

A₃ = 0.4 A

Then combines again:

A₄ = 0.8 A

4 0

2 years ago

An object accelerates from rest and travels 53 m west in 5.2 s. Determine the acceleration

zmey [24]

Answer:

20.4m/s²

Explanation:

Given parameters:

Initial velocity = 0m/s

Distance = 53m

Time = 5.2s

Unknown:

Acceleration = ?

Solution:

This is a linear motion and we use the right motion equation;

S = ut + $\frac{1}{2}$ at²

S is the distance

u is the initial velocity

a is the acceleration

t is the time

Insert the parameters and solve;

53 = (0x 5.2) + $\frac{1}{2}$ x a x 5.2

53 = 2.6a

a = $\frac{53}{2.6}$ = 20.4m/s²

6 0

3 years ago