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3 years ago

Do all types of light change materials in the same way

2 answers:

4 0

Transparent and translucent materials transmit most of the light that strikes them, but not all of it. Light can also
reflect off these materials. When light reflects, it is bouncing off something. Windows transmit most of the light that strikes them, but they also reflect light. If you have a lamp turned on near a window at night, you can see the reflection of the lamp in the window.
Transparent and translucent materials also absorb some of the light that strikes them. When something absorbs light, it is soaking up the light. When light is absorbed by an object, the light energy changes to heat energy and the object heats up. If you touch a window that has been in the sunlight, you will notice that it is warm.
Opaque materials do not transmit any light. All of the light that strikes an opaque material is reflected or absorbe

pochemuha3 years ago

4 0

Light can be reflected, transmitted, or absorbed. You have read that EM waves can interact with a material medium in the same ways that mechanical waves do. Most things are visible because they reflect light. The two other forms of interaction are transmission and absorption.

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6. When sodium and oxygen react to form an ionic compound, the mass of the compound ____ the sum of the masses of the individual

arsen [322]

Because there’s no elemental degradation, the mass of the compound EQUALS the sum of the masses.

3 0

3 years ago

A 2.0-cm-diameter parallel-plate capacitor with a spacing of 0.50 mm is charged to 200 V?What is the total energy stores in the

Rama09 [41]

1) $1.11\cdot 10^{-7} J$

The capacitance of a parallel-plate capacitor is given by:

$C=\frac{\epsilon_0 A}{d}$

where

$\epsilon_0$ is the vacuum permittivity

A is the area of each plate

d is the distance between the plates

Here, the radius of each plate is

$r=\frac{2.0 cm}{2}=1.0 cm=0.01 m$

so the area is

$A=\pi r^2 = \pi (0.01 m)^2=3.14\cdot 10^{-4} m^2$

While the separation between the plates is

$d=0.50 mm=5\cdot 10^{-4} m$

So the capacitance is

$C=\frac{(8.85\cdot 10^{-12} F/m)(3.14\cdot 10^{-4} m^2)}{5\cdot 10^{-4} m}=5.56\cdot 10^{-12} F$

And now we can find the energy stored,which is given by:

$U=\frac{1}{2}CV^2=\frac{1}{2}(5.56\cdot 10^{-12} F/m)(200 V)^2=1.11\cdot 10^{-7} J$

2) 0.71 J/m^3

The magnitude of the electric field is given by

$E=\frac{V}{d}=\frac{200 V}{5\cdot 10^{-4} m}=4\cdot 10^5 V/m$

and the energy density of the electric field is given by

$u=\frac{1}{2}\epsilon_0 E^2$

and using

$E=4\cdot 10^5 V/m$ , we find

$u=\frac{1}{2}(8.85\cdot 10^{-12} F/m)(4\cdot 10^5 V/m)^2=0.71 J/m^3$

7 0

4 years ago

A wind turbine is rotating at 15 rpm under steady winds flowing through the turbine at a rate of 42,000 kg/s. The tip velocity o

zzz [600]

Answer:

a) 5.22 m/s

b) 31.4 %

Explanation:

f = rotating speed = 15 rpm = 15/60 =0.25 rps

m = Mass flow rate of air = 42000 kg/s

v = Tip velocity = 250 km/h = 250/3.6 = 69.44 m/s

W = Work output = 180 kW

A = Swept area of wind turbine

r = Radius of wind turbine

η = Efficiency

$r=\frac{v}{2\pi f}\\\Rightarrow r=\frac{250\div 3.6}{2\pi 0.25}=\frac{250}{1.8\pi}$

$A=\pi r^2\\\Rightarrow A=\pi\left(\frac{250}{1.8\pi}\right)^2\\\Rightarrow A=\left(\frac{250}{1.8}\right)^2\frac{1}{\pi}$

$m=\rho V\\\Rightarrow m=\rho vA\\\Rightarrow v=\frac{m}{\rho A}\\\Rightarrow v=\frac{42000}{1.31 \left(\frac{250}{1.8}\right)^2\frac{1}{\pi}}\\\Rightarrow v=5.22\ m/s$

∴ The average velocity of the air is 5.22 m/s

$E=m\frac{v^2}{2}=42000\frac{5.22^2}{2}\\\Rightarrow E=572538.92$

$\eta=\frac{W}{E}=\frac{180000}{572538.92}\\\Rightarrow \eta =0.314$

∴ Conversion efficiency of the turbine is 0.314 or 31.4 %

7 0

3 years ago

Read 2 more answers

The atoms ,molecules,or compound present at the start of a chemical reaction that parcitipate in the reaction . which part of a

Tomtit [17]

Answer:

The atoms ,molecules, or compound present at the start of a chemical reaction that parcitipate in the reaction are the reactants.

Explanation:

The chemical reaction is the way in which one substance reacts against another. So, a chemical reaction consists of the transformation of some substances into others, that is, the process of arranging atoms and bonds when chemical substances come into contact.

In a chemical reaction, the initial substances are called reactants, while the new substances obtained are called products.

So, the atoms ,molecules, or compound present at the start of a chemical reaction that parcitipate in the reaction are the reactants.

8 0

4 years ago

The hindenburg zeppelin contained 200,000 m^3 of hydrogen, with a density of 0.0899 kg/m^3. What is the mass of the hydrogen?

oksian1 [2.3K]

d=m/v

0.0899=m/200000

or,0.0899*200000=m

m=17980

6 0

3 years ago

Read 2 more answers