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Bad White [126]
3 years ago
11

What is the definition of a point object?

Physics
1 answer:
Kaylis [27]3 years ago
4 0
Point object is an expression that is used in Kinematics. It refers the object whose dimensions are ignored or neglected and is treated as a dot object to simplify the calculations. When the object is treated as a point object it means the whole mass is summed in one point, you can imagine it as a sphere which has the mass and the radius is 0...
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What are the three points of the fire triangle
prisoha [69]
1-fuel
2-heat
3-oxygen
5 0
3 years ago
Dierdre drew a diagram to compare the three types of mirrors.
Sholpan [36]

<em>Labels that belong in the marked ares X, Y & Z include;</em>

X: Curves outward

Y: Image may be smaller than object

Z: Image is always virtual

<u>Since the rays never meet, the images formed by convex mirrors are always virtual and smaller than the object, and since they are smaller, the images appear to be further than they actually are.</u>

8 0
3 years ago
What are the characteristics of the radiation emitted by a blackbody? According to Wien's Law, how many times hotter is an objec
jasenka [17]

Answer:

a) What are the characteristics of the radiation emitted by a blackbody?

The total emitted energy per unit of time and per unit of area depends in its temperature (Stefan-Boltzmann law).

The peak of emission for the spectrum will be displaced to shorter wavelengths as the temperature increase (Wien’s displacement law).

The spectral density energy is related with the temperature and the wavelength (Planck’s law).

b) According to Wien's Law, how many times hotter is an object whose blackbody emission spectrum peaks in the blue, at a wave length of 450 nm, than a object whose spectrum peaks in the red, at 700 nm?

The object with the blackbody emission spectrum peak in the blue is 1.55 times hotter than the object with the blackbody emission spectrum peak in the red.

Explanation:

A blackbody is an ideal body that absorbs all the thermal radiation that hits its surface, thus becoming an excellent emitter, as these bodies express themselves without light radiation, and therefore they look black.

The radiation of a blackbody depends only on its temperature, thus being independent of its shape, material and internal constitution.

If it is study the behavior of the total energy emitted from a blackbody at different temperatures, it can be seen how as the temperature increases the energy will also increase, this energy emitted by the blackbody is known as spectral radiance and the result of the behavior described previously is Stefan's law:

E = \sigma T^{4}  (1)

Where \sigma is the Stefan-Boltzmann constant and T is the temperature.

The Wien’s displacement law establish how the peak of emission of the spectrum will be displace to shorter wavelengths as the temperature increase (inversely proportional):

\lambda max = \frac{2.898x10^{-3} m. K}{T}   (2)

Planck’s law relate the temperature with the spectral energy density (shape) of the spectrum:

E_{\lambda} = {{8 \pi h c}\over{{\lambda}^5}{(e^{({hc}/{\lambda \kappa T})}-1)}}}  (3)

b) According to Wien's Law, how many times hotter is an object whose blackbody emission spectrum peaks in the blue, at a wavelength of 450 nm, than a object whose spectrum peaks in the red, at 700 nm?

It is need it to known the temperature of both objects before doing the comparison. That can be done by means of the Wien’s displacement law.

Equation (2) can be rewrite in terms of T:

T = \frac{2.898x10^{-3} m. K}{\lambda max}   (4)

Case for the object with the blackbody emission spectrum peak in the blue:

Before replacing all the values in equation (4), \lambda max (450 nm) will be express in meters:

450 nm . \frac{1m}{1x10^{9} nm}  ⇒ 4.5x10^{-7}m

T = \frac{2.898x10^{-3} m. K}{4.5x10^{-7}m}

T = 6440 K

Case for the object with the blackbody emission spectrum peak in the red:

Following the same approach above:

700 nm . \frac{1m}{1x10^{9} nm}  ⇒ 7x10^{-7}m

T = \frac{2.898x10^{-3} m. K}{7x10^{-7}m}

T = 4140 K

Comparison:

\frac{6440 K}{4140 K} = 1.55

The object with the blackbody emission spectrum peak in the blue is 1.55 times hotter than the object with the blackbody emission spectrum peak in the red.

4 0
3 years ago
5. Two charged particles are separated by a distance of 12 meters. The Coulomb force between them is 20 N. What will the Coulomb
Leni [432]

Answer:

A) 80 N

Explanation:

The closer the particles get, the stronger the Coulomb force, which elongates choices C and D. The Coulomb force is inversely proportional to the distance squared. If the distance is cut in half, the force is multiplied by the reciprocal of (1/2)^2, which is 4. Multiplying it out, 20 times 4 is 80 N.

8 0
2 years ago
Use this table of a school bus during morning pickups to calculate its average speed between 0 h and 2.340 h.
Gelneren [198K]

The average speed between 0 h and 2.340 h is 6.97 Km/h

Average speed is defined as the total distance travelled divided by the total time taken to cover the distance.

Average \: speed =  \frac{total \: distance}{total \: time}  \\  \\

With the above formula, we can obtain the average speed between 0 h and 2.340 h as illustrated below:

  • Total time = 2.340 – 0 = 2.340 h
  • Total distance = 16.3 – 0 = 16.3 Km
  • Average speed =?

Average \: speed =  \frac{total \: distance}{total \: time}  \\  \\Average \: speed =  \frac{16.3}{2.340}  \\  \\ Average \: speed = 6.97 \: Km/h \\  \\

Learn more about average speed: brainly.com/question/24884027

8 0
2 years ago
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