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Luda [366]
2 years ago
9

Quando aquecemos água em nossas casas, ao nível do mar, utilizando um recipiente aberto, sua temperatura nunca ultrapassa os 100

°C. Isso ocorre porque:
a) ao atingir essa temperatura, a agua perde sua capacidade de absorver calor.
b) ao atingir essa temperatura, a agua passa a perder exatamente a mesma quantidade de calor que esta recebendo, mantendo assim a temperatura constante.
c) as mudanças de fase ocorrem à temperatura constante.
d) ao atingir essa temperatura, a agua começa a expelir o oxigenio e outros gases nela dissolvidos.
e) as mudanças de fases de agua sempre ocorrem em 100 graus Celsius
Physics
1 answer:
iren2701 [21]2 years ago
4 0

Answer:

i dont speak spanish

Explanation:

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A source produces 20 crests and 20 troughs in 4 seconds. The second crest is 3 cm away from the first crest.Calculate :
sineoko [7]

Answer:

Solution given:

No of waves[N] =20crests & 20 troughs

=20waves

Time[T]=4seconds

distance[d]=3cm=0.03m

Now

<u>Wave</u><u> </u><u>length</u><u>=</u>3cm=3 × {10}^{ - 2}m

<u>Frequency</u>=\frac{No of waves}{time}

=\frac{20}{4}=5Hertz

and

Wave speed:wave length×frequency=3 × {10}^{ - 2}m×5=1.5 × {10}^{ - 1} \tt{ {ms}^{ - 1}}.

3 0
2 years ago
A person is nearsighted with a far point of 75.0 cm. a. What focal length contact lens is needed to give him normal vision
BigorU [14]

Complete Question

The  complete question is  shown on the first uploaded image  

Answer:

a

  f=  -75 \ cm =  - 0.75 \ m

b

  P  =  -1.33 \ diopters

Explanation:

From the question we are told that

    The  image distance is  d_i =  -75 cm

The value of the image is negative because it is on the same side with the corrective glasses

    The  object distance is  d_o =  \infty

The  reason object distance  is because the object father than it being picture by the eye

General focal length is mathematically represented as

              \frac{1}{f}  =  \frac{1}{d_i}  -   \frac{1}{d_o}

substituting values

             \frac{1}{f}  =  \frac{1}{-75}  -   \frac{1}{\infty}

=>         f=  -75 \ cm =  - 0.75 \ m

Generally the power of the corrective lens is  mathematically represented as

        P  =  \frac{1}{f}

substituting values

       P  =  \frac{1}{-0.75}

        P  =  -1.33 \ diopters

7 0
3 years ago
In the diagrams, the solid green line represents Earth's rotational axis and the dashed red line represents the magnetic field a
Elis [28]

Answer:

b

Explanation:

5 0
3 years ago
Read 2 more answers
Electrons surround the nucleus of an atom and those that are in the outer energy levels are _____.
balandron [24]
More attracted to the nucleus because they are further from the nucleus. In addition, the screening effect, repulsion of inner electrons on the valence electrons, will effectively reduce the attraction of the valence electrons toward the nucleus.
4 0
3 years ago
Resistors and reactors, for use over 600 volts, shall not be installed in close enough proximity to combustible materials to con
suter [353]

Resistors and reactors, for use over 600 volts, shall not be installed in close enough proximity to combustible materials to constitute a fire hazard and shall have a clearance of not less than<u> 300 mm </u>from combustible materials.

Explanation:

  • The hazards associated with high power industrial resistors are primarily due to their open construction, which is necessary for cooling.
  • The exposed conductors which make up the resistors can be not only a shock hazard but also a thermal burn hazard.
  • When a resistor fails, it either goes open or the resistance increases. When the resistance increases, it can burn the board, or burn itself up.
  • Avoid touching non-flammable resistors in operation; the surface temperature ranges from approximately 350 °C to 400°C when utilized at the full rated value. Maintaining a surface temperature of 200°C or less will extend resistors service life.
  • Do not apply power to a circuit while measuring resistance. When you are finished using an ohmmeter, switch it to the OFF position if one is provided and remove the leads from the meter.
  • Always adjust the ohmmeter for 0 (or in shunt ohmmeter) after you change ranges before making the resistance measurement.

4 0
3 years ago
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