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Sliva [168]
3 years ago
8

1. An excited lithium atom emits a red light with wavelength a = 671nm. What is the corresponding photon energy? hc (6.63 x 10-3

4).S)(3.0 x 108m/s)​
Physics
1 answer:
Rudiy273 years ago
6 0

Answer:

 E = 2,964 10⁻¹⁹ J

Explanation:

The energy of the photons is given by the Planck relation

          E = h f

the speed of light is related to wavelength and frequency

          c = λ f

we substitute

          E = h c /λ

let's reduce the magnitude to the SI system

          λ = 671 nm = 671 10⁻⁹ m

let's calculate

          E = 6.63 10⁻³⁴ 3 10⁸ /671 10⁻⁹

          E = 2,964 10⁻¹⁹ J

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A heat-conducting rod consists of an aluminum section, 0.30 m long, and a copper section, .70m long. Both sections have a cross-
Igoryamba
Thermal conductions
K= QL/ART
Aluminium T₁ = 10 + 273.15
                    T₂ = 283.15k
205 = 2.0  × 0.30/4× 10⁻⁴ × (T₂ - 283.15)
Copper
385 = Q × 0.70/4×10⁻⁴ ×(433.15 - T₂)
Where T₃ = 160 + 273.15
T₃ = 433.15K
From 2 to 3
205/385 = 0.30/0.70 × 433.15 - T₂/T₂ - 283.15
= 0.53T₂ -150.06 = 181.92 - 0.42 T₂
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T₂ = 76.3°c
=77°c.

6 0
3 years ago
Psychological profiling is also known as criminal profiling. True or False?
Nikolay [14]
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8 0
3 years ago
Read 2 more answers
.You have always been impressed by the speed of the elevators in your apartment building. You wonder about the maximum accelerat
AlexFokin [52]

Answer:

5.51 m/s^2

Explanation:

Initial scale reading = 50 kg  

assume the greatest scale reading = 78.09 kg

<u>Determine the maximum acceleration for these elevators</u>

At rest the weight is = 50 kg

Weight ( F ) = mg = 50 * 9.81 = 490.5 N<u> </u>

<u> </u>At the 10th floor weight = 78.09 kg

Weight at 10th floor ( F ) = 78.09 * 9.81 = 766.11 N

F = change in weight

Change in weight( F ) = ma = 766.11 - 490.5 (we will take the mass as the starting mass as that mass is calculated when the body is at rest)

50 * a = 275.61

Hence the maximum acceleration ( a ) = 275.61 / 50 = 5.51 m/s^2

3 0
3 years ago
Aparticlewhosemassis2.0kgmovesinthexyplanewithaconstantspeedof3.0m/s along the direction r = i + j . What is its angular momentu
svetoff [14.1K]

Answer:

\vec{L}=-30\frac{kgm^2}{s}\hat{k}

Explanation:

In order to calculate the angular momentum of the particle you use the following formula:

\vec{L}=\vec{r}\ X\ \vec{p}       (1)

r is the position vector respect to the point (0 , 5.0), that is:

r = 0m i + 5.0m j    (2)

p is the linear momentum vector and it is given by:

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the direction of p comes from the fat that the particle is moving along the i + j direction.

Then, you use the results of (2) and (3) in the equation (1) and solve for L:

\vec{L}=-30\frac{kgm^2}{s}\hat{k}

The angular momentum is -30 kgm^2/s ^k

8 0
3 years ago
Why are there only two elements in the first period of the periodic table?(1 point)
tester [92]

Answer:

because each row increases in atomic mass by a specific number, so anything over five is in the second row.

8 0
2 years ago
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