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vladimir1956 [14]
3 years ago
8

In this circuit (see picture), which resistor will draw the least power?

Physics
1 answer:
Basile [38]3 years ago
3 0
A few different ways to do this: 

Way #1: 
The current in the series loop is  (12 V) / (total resistance) . 
(Turns out to be 2 Amperes, but the question isn't asking for that.)

In a series loop, the current is the same at every point, so it's
the same current through each resistor.

The power dissipated by a resistor is  (current)² · (resistance),
and the current is the same everywhere in the circuit, so the
smallest resistance will dissipate the least power.  That's  R1 .

And by the way, it's not "drawing" the most power.  It's dissipating it.

Way #2:
Another expression for the power dissipated by a resistance is

                 (voltage across the resistance)²  /  (resistance)  .

In a series loop, the voltage across each resistor is

          [ (individual resistance) / (total resistance ] x battery voltage.

So the power dissipated by each resistor is

         (individual resistance)² x [(battery voltage) / (total resistance)²]

This expression is smallest for the smallest individual resistance.
(The other two quantities are the same for each individual resistor.)
So again, the least power is dissipated by the smallest individual resistance.
That's R1 .                                      

Way #3:  (Einstein's way)
If we sat back and relaxed for a minute, stared at the ceiling, let our minds
wander, puffed gently on our pipe, and just daydreamed about this question
for a minute or two, we might have easily guessed at the answer.

===>  When you wire up a battery and a light bulb in series, the part
that dissipates power, and gets so hot that it radiates heat and light, is
the light bulb (some resistance), not the wire (very small resistance).
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Explanation:

It is given that,

Length of the copper wire, l = 4.4 m

Diameter of copper wire, d = 1.3 mm = 0.0013 m

Radius of copper wire, r = 0.00065 m

The resistivity of the copper wire, \rho=1.68\times 10^{-8}\ \Omega-m

We need to find the resistance of the copper wire. It is given by :

R=\rho\dfrac{l}{A}

R=1.68\times 10^{-8}\ \times \dfrac{4.4\ m}{\pi (0.00065)^2}

R =0.055 ohms

So, the resistance of the copper wire is 0.055 ohms. Hence, this is the required solution.

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3 years ago
One clue we can observe that means a chemical reaction has occurred is the formation of light. What is one chemical reaction you
dimaraw [331]

Answer:

There are five signs of a chemical change:

Color Change.

Production of an odor.

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Explanation:

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8 0
3 years ago
In the diagram, the arrow shows the movement of electric charges through a wire connected to a battery.
solong [7]

Due to difference in electric potential.

<h3>What is Potential difference?</h3>

The amount of work in an electrical field to move a unit charge from one place to another is known as the electrical potential difference.

Here , the potential difference is the difference in electric potential between two charged substances.

Current is the flow of charges from one end end to another end of a conducting wire connected across a two terminals of a battery.

The potential difference is [provided by the battery across the two terminals due which the charges flow.

Current flow is from positive to negative terminals, indicating the movement of positive charges in that direction.

Hence , potential difference causes the electric charges to flow from one end of the battery .

Learn more about the flow of current : brainly.com/question/2264542

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6 0
2 years ago
40 POINTS!!! + BRAINLIEST!!!
Sergeu [11.5K]

Answer:

I think it is better if you read and shortly write my explanation

Explanation:

simple pendulum with no friction, mechanical energy is conserved. Total mechanical energy is a combination of kinetic energy and gravitational potential energy. As the pendulum swings back and forth, there is a constant exchange between kinetic energy and gravitational potential energy.

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3 years ago
If light has a speed of 122,000 mps in a transparent medium, what is the index of refraction of the medium? A. n = 1.52
castortr0y [4]

Answer:

A.\hspace{3}n=1.52

Explanation:

The refractive index of a medium is a measure to know how much the speed of light within the medium is reduced. It can be calculated with the next equation:

n=\frac{c}{v}   (1)

Where:

c=Speed\hspace{3}of\hspace{3}light\hspace{3}in\hspace{3}vacuum\\n=Refractive\hspace{3}index\\

v=Velocity\hspace{3}of\hspace{3}light\hspace{3}in\hspace{3}the\hspace{3}medium

The speed of light in the vacuum is approximately 300,000 km/s. In order to work with the same units let's do the proper conversion with the velocity of the medium:

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Finally, replacing the data in (1):

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3 0
3 years ago
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