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3 years ago

15

A hair dryer with a resistance of 9.6 ohms operates at 120 volts for 2.5 minutes. The total electrical energy used by the dryer

during this time interval is

1 answer:

Talja [164]3 years ago

5 0

Answer:

$2.25\cdot 10^5 J$

Explanation:

First of all, we have to find the power used by the hair dryer, which is given by

$P=\frac{V^2}{R}$

where

V = 120 V is the voltage

$R=9.6 \Omega$ is the resistance of the hair dryer

Substituting,

$P=\frac{(120 V)^2}{9.6 \Omega}=1500 W$

Now we can find the total electrical energy used, given by

$E=Pt$

where P is the power and

t = 2.5 min = 150 s is the time

Substituting,

$E=(1500 W)(150 s)=2.25\cdot 10^5 J$

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A wildlife photographer uses a moderate telephoto lens of focal length 135 mm and maximum aperture f/4.00 to photograph a bear t

labwork [276]

Answer:

<h3>(A) The width $x = 0.24 \times 10^{-3}$ m</h3><h3>(B) The new width is $1.32 \times 10^{-3}$ m</h3>

Explanation:

Given :

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Maximum aperture $D = \frac{f}{4}$

Wavelength $\lambda = 550 \times 10^{-9}$ m

(A)

From rayleigh criterion,

$\theta = \frac{1.22 \lambda }{D}$

$\theta =\frac{ 1.22 \times 550 \times 10^{-9} }{33.75 \times 10^{-3} }$

$\theta = 1.98 \times 10^{-5}$ rad

From angle formula,

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Where $R =$ 12 m ( given in example )

$x = 12 \times 1.98 \times 10^{-5}$ m

$x = 23.76 \times 10^{-5}$

$x = 0.24 \times 10^{-3}$ m

(B)

We know that $\theta$ is proportional to the $x$ and inversely proportional to the $D$

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$x = 0.24 \times 10^{-3} \times \frac{22}{4}$

$x = 1.32 \times 10^{-3}$ m

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Mrrafil [7]

That statement is true.

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Hope this helps

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lianna [129]

The air movements toward the equator are called trade winds, which are warm, steady breezes that blowalmost continuously. The Coriolis Effect makes the trade winds appear to be curving to the west, whether they are traveling to the equator from the south or north. Answer trade wind

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A cup of coffee is sitting on a table in a train that is moving with a constant velocity. The coefficient of static friction bet

Vikki [24]

Answer:

a = 2.94 m/s²

Explanation:

In order for the cup not to slip, the unbalanced force on cup must be equal to the frictional force:

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ma = μR = μW

ma = μmg

a = μg

where,

a = maximum acceleration for the cup not to slip = ?

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Therefore,

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solniwko [45]

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