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3 years ago

Light intensity is?

Physics

2 answers:

IRISSAK [1]3 years ago

6 0

Answer:

The rate at which a waves energy flows through a given unit of area

Fittoniya [83]3 years ago

5 0

The correct answer is:
<span>The rate at which a waves energy flows through a given unit of area

In fact, light intensity is defined as the light power per unit of area:
</span> $I= \frac{P}{A}$
<span>but the power is the energy carried by the light per unit of time:
</span> $P= \frac{E}{t}$
<span>this means that the intensity can be rewritten as
</span> $I= \frac{E}{tA}$ <span>
So, it's basically the rate of energy (per unit of time) through a given surface.</span>

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An average hole drift velocity of 103 cm/sec results when 2 V is applied across a 1 cm long semiconductor bar. What is the hole

Helga [31]

Answer:

ε = 2 V/cm

Explanation:

To calculate the mobility inside this bar, we just need to apply the expression that let us determine the mobility. This expression is the following:

ε = ΔV / L

Where:

ε: Hole mobility inside the bar

ΔV: voltage applied in the bar

L: Length of the bar

We already have the voltage and the length so replacing in the above expression we have:

ε = 2 V / 1 cm

The data of the speed can be used for further calculations, but in this part its not necessary.

Hope this helps

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3 years ago

Two resistors of 15 and 30 ω are connected in parallel. if the combination is connected in series with a 9. 0-v battery and a 20

Stels [109]

Resistors Working Together.

Resistors are shown coupled in parallel to a voltage source in Figure 10.3.4. When all of the resistors' ends are connected to one another by a continuous wire of minimal resistance and their other ends are also connected to one another by a continuous wire of minimal resistance, the resistors are said to be in parallel. There is a constant potential drop across all resistors. Ohm's law, I=V/R, can be used to determine the current flowing through each resistor while the voltage is constant across each resistor. For instance, the headlights, radio, and other components of an automobile are linked in parallel so that each subsystem can use the entire voltage of the source and function independently. The wiring in your home or any other structure shares the same

The original circuit is shown in part a with two parallel resistors linked to a voltage source, and the equivalent circuit is shown in part b with one equivalent resistor connected to the voltage source.

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#4159

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2 years ago

A truck was carrying a substance in a tank. The molecules of that substance were moving away from each other. The truck parked o

DochEvi [55]

Answer:

In the morning the molecules were moving away from each other with a smaller speed than when the truck was carrying the substance.

Explanation:

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2 years ago

Two particles with masses 2m and 9m are moving toward each other along the x axis with the same initial speeds vi. Particle 2m i

s2008m [1.1K]

Answer:

The final speed for the mass 2m is $v_{2y}=-1,51\ v_{i}$ and the final speed for the mass 9m is $v_{1f} =0,85\ v_{i}$ .

The angle at which the particle 9m is scattered is $\theta = -66,68^{o}$ with respect to the - y axis.

Explanation:

In an elastic collision the total linear momentum and the total kinetic energy is conserved.

<u>Conservation of linear momentum:</u>

Because the linear momentum is a vector quantity we consider the conservation of the components of momentum in the x and y axis.

The subindex 1 will refer to the particle 9m and the subindex 2 will refer to the particle 2m

$\vec{p}=m\vec{v}$

$p_{xi} =p_{xf}$

In the x axis before the collision we have

$p_{xi}=9m\ v_{i} - 2m\ v_{i}$

and after the collision we have that

$p_{xf} =9m\ v_{1x}$

In the y axis before the collision $p_{yi} =0$

after the collision we have that

$p_{yf} =9m\ v_{1y} - 2m\ v_{2y}$

$p_{xi} =p_{xf} \\7m\ v_{i} =9m\ v_{1x}\Rightarrow v_{1x} =\frac{7}{9}\ v_{i}$

then

$p_{yi} =p_{yf} \\0=9m\ v_{1y} -2m\ v_{2y} \\v_{1y}=\frac{2}{9} \ v_{2y}$

<u>Conservation of kinetic energy:</u>

$\frac{1}{2}\ 9m\ v_{i} ^{2} +\frac{1}{2}\ 2m\ v_{i} ^{2}=\frac{1}{2}\ 9m\ v_{1f} ^{2} +\frac{1}{2}\ 2m\ v_{2f} ^{2}$

$\frac{11}{2}\ m\ v_{i} ^{2} =\frac{1}{2} \ 9m\ [(\frac{7}{9}) ^{2}\ v_{i} ^{2}+ (\frac{2}{9}) ^{2}\ v_{2y} ^{2}]+ m\ v_{2y} ^{2}$

Putting in one side of the equation each speed we get

$\frac{25}{9}\ m\ v_{i} ^{2} =\frac{11}{9}\ m\ v_{2y} ^{2}\\v_{2y} =-1,51\ v_{i}$

We know that the particle 2m travels in the -y axis because it was stated in the question.

Now we can get the y component of the speed of the 9m particle:

$v_{1y} =\frac{2}{9}\ v_{2y} \\v_{1y} =-0,335\ v_{i}$

the magnitude of the final speed of the particle 9m is

$v_{1f} =\sqrt{v_{1x} ^{2}+v_{1y} ^{2} }$

$v_{1f} =\sqrt{(\frac{7}{9}) ^{2}\ v_{i} ^{2}+(-0,335)^{2}\ v_{i} ^{2} }\Rightarrow \ v_{1f} =0,85\ v_{i}$

The tangent that the speed of the particle 9m makes with the -y axis is

$tan(\theta)=\frac{v_{1x} }{v_{1y}} =-2,321 \Rightarrow\theta=-66,68^{o}$

As a vector the speed of the particle 9m is:

$\vec{v_{1f} }=\frac{7}{9} v_{i} \hat{x}-0,335\ v_{i}\ \hat{y}$

As a vector the speed of the particle 2m is:

$\vec{v_{2f} }=-1,51\ v_{i}\ \hat{y}$

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3 years ago

Nellie newton swings a rock into a circular path while holding an attached string overhead. the string makes a 45-degree angle t

taurus [48]

Horizontal component of the string tension

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3 years ago