Guest #4134

2 months ago

No its false now I'm just going to type because I need 20 or more characters to answer this question....

Question

A crying baby emits sound with an intensity of 8.0 × 10-8 w/m2. calculate a reasonable estimate for the intensity level from a set of quintuplets (five babies), all crying simultaneously at the same place? the lowest detectable intensity is 1.0 × 10-12 w/m2.

Solution 1

Sound intensity of 1 baby, I = 8*10^-8 W/m^2

The sound heard should be higher by:

10*log (n) where for 5 babies, n = 5. Then

10*log (n) = 10*log (5) ≈ 7 dB

Also give is the reference sound, Io = 1.0*10^-12 W/m^2

Therefore,

Sound intensity, L1 = 10*log (I/I1) = 10*log [(8*10^-8)/(1*10^-12)] ≈ 49 dB

Therefore, total intensity for the five babies is:

Total intensity = 49+7 = 56 dB

The sound heard should be higher by:

10*log (n) where for 5 babies, n = 5. Then

10*log (n) = 10*log (5) ≈ 7 dB

Also give is the reference sound, Io = 1.0*10^-12 W/m^2

Therefore,

Sound intensity, L1 = 10*log (I/I1) = 10*log [(8*10^-8)/(1*10^-12)] ≈ 49 dB

Therefore, total intensity for the five babies is:

Total intensity = 49+7 = 56 dB

Solution 2

**The intensity level from a set of quintuplets (five babies) : ****56 dB**

**Wave intensity** is the power of a wave that is moved through a plane of one unit that is perpendicular to the direction of the wave

Can be formulated

I = intensity, W m⁻²

P = power, watt

A = area, m²

The farther the distance from the sound source, the smaller the intensity

So the intensity is inversely proportional to the square of the distance from the source

Intensity level (LI) can be formulated

Io = 10⁻¹²

For the level of intensity of several sound sources as many as n pieces can be formulated:

The intensity level of 1 baby is

LI = 10 log 8.10⁴

LI = 49

The intensity level of 5 babies :

LI5 = LI + 10 log n

LI5 = 49 + 10 log 5

LI5 = 49 + 7

**LI5 = 56 **

**The intensity of a laser beam **

**electric field **

**magnetism **

Question

Make a rule: how would you find the resistance of a parallel circuit with n identical resistors?

Solution 1

When n resistors are connected in parallel, it means they are connected to the same potential difference V:

(2)

It also means that the total current in the circuit is given by the sum of the currents flowing through each branch (each resistor) of the circuit:

(1)

By using Ohm's law:

we can rewrite (1) as

However, we said that the potential difference across each resistor is equal (eq.(2)), so we can rewrite the last formula as

From which we find an expression for the equivalent resistance of n resistors in parallel:

(2)

It also means that the total current in the circuit is given by the sum of the currents flowing through each branch (each resistor) of the circuit:

(1)

By using Ohm's law:

we can rewrite (1) as

However, we said that the potential difference across each resistor is equal (eq.(2)), so we can rewrite the last formula as

From which we find an expression for the equivalent resistance of n resistors in parallel:

Question

A cello string 0.75 m long has a 220 hz fundamental frequency. find the wave speed along the vibrating string. answer in units of m/s.

Solution 1

For fundamental frequency of a string to occur, the length of the string has to be half the wavelength. That is,

1/2y = L, where L = length of the string, y = wavelength.

Therefore,

y = 2L = 2*0.75 =1.5 m

Additionally,

y = v/f Where v = wave speed, and f = ferquncy

Then,

v = y*f = 1.5*220 = 330 m/s

1/2y = L, where L = length of the string, y = wavelength.

Therefore,

y = 2L = 2*0.75 =1.5 m

Additionally,

y = v/f Where v = wave speed, and f = ferquncy

Then,

v = y*f = 1.5*220 = 330 m/s

Question

A car has two horns, one emitting a frequency of 199 hz and the other emitting a frequency of 203 hz. what beat frequency do they produce?

Solution 1

Beat frequency, fb = |f2-f1|

That is, beat frequency is the absolute difference between two frequencies. Is is as a results of destructive and constructive inferences.

Therefore, in this case:

fb = 203 - 199 = 4 Hz

That is, beat frequency is the absolute difference between two frequencies. Is is as a results of destructive and constructive inferences.

Therefore, in this case:

fb = 203 - 199 = 4 Hz

Question

Extend your thinking: household appliances are usually connected in a parallel circuit. why do you think it might be a problem if too many appliances are turned on at once? (hint: current in a wire also produces heat.)

Solution 1

There might be a problem of a lot of **power** being **dissipated** if too many

appliances are turned on at **once.**

We can infer from **Ohm's law** that as **resistance** decreases, the total **current** increases.

**I= V/R**

The **power** dissipated through the circuit is directly proportional to the **square**

of the **current**.

**P= I²R**

We can therefore state that the **power** dissipated via heat will be much when

too many **appliances** are turned on at **once**.

Read more about **Electricity** here brainly.com/question/25144822

Solution 2

The equivalent resistance of several devices connected in parallel is given by

where are the resistances of the various devices. We can see that every time we add a new device in parallel, the term increases, therefore the equivalent resistance of the circuit decreases.

But Ohm's law:

tells us that if the equivalent resistance decreases, the total current in the circuit increases. The power dissipated through the circuit (and so, the heat produced) depends on the square of the current:

therefore if there are too many devices connected in parallel, this can be a problem because there could be too much power dissipated (and too much heat) through the circuit.

where are the resistances of the various devices. We can see that every time we add a new device in parallel, the term increases, therefore the equivalent resistance of the circuit decreases.

But Ohm's law:

tells us that if the equivalent resistance decreases, the total current in the circuit increases. The power dissipated through the circuit (and so, the heat produced) depends on the square of the current:

therefore if there are too many devices connected in parallel, this can be a problem because there could be too much power dissipated (and too much heat) through the circuit.

Question

Apply: what will be the total resistance and current in a parallel circuit with a 15-volt battery and three 10-ohm resistors? test your answers with the gizmo.

Solution 1

1) Total resistance

the total resistance of a circuit with n resistors in parallel is given by

where are the single resistances.

In our circuit, we have 3 resistors of each, so the total resistance of the circuit is given by

which means a total resistance of

2) Current in the circuit

The current in the circuit can be found by using Ohm's law:

where V is the voltage of the battery and Req is the total resistance we found before. By using V=15 V, we find

the total resistance of a circuit with n resistors in parallel is given by

where are the single resistances.

In our circuit, we have 3 resistors of each, so the total resistance of the circuit is given by

which means a total resistance of

2) Current in the circuit

The current in the circuit can be found by using Ohm's law:

where V is the voltage of the battery and Req is the total resistance we found before. By using V=15 V, we find

Question

Lion and leopard are two of Africa's large cat ____.

Solution 1

The fill in blank would be breeds.

Lions and leopards are both cats, but they are different kinds.

I hope this helps! Let me know if you need further explanation.

~Brooke❤️

Lions and leopards are both cats, but they are different kinds.

I hope this helps! Let me know if you need further explanation.

~Brooke❤️

Question

What is an advantage of using coal power over solar power to generate electricity

Solution 1

An advantage of using **coal power** over **solar power** to generate electricity is Reliable Fuel.

Compared to solar power or wind energy, **coal** is a reliable, predictable, and dependable fuel. While it may not be at the forefront of national energy production, it can provide invaluable backup service and highly reliable fuel.

**"Coal-fired power **plants burn coal to make** steam** and the steam turns turbines (machines for generating rotary mechanical power) to generate **electricity**." Many industries and businesses have their own power plants, and some use coal to generate electricity for their own use and mostly in combined **heat** and power plants.

**"Solar power** works by converting energy from the sun into power." There are two forms of **energy **generated from the sun for our use – electricity and heat. Both are generated through the use of **solar panels**, which range in size from residential rooftops to '**solar farms**' stretching over acres of rural land.

Know more about **coal power **here

#SPJ3

Solution 2

**Answer:**

Coal power can be generated at night

**Explanation:**

Question

Which of the following statements about nuclear power is true? A.
Nuclear power plants are cheap to build, but expensive to operate.
B.
Nuclear power plants are more expensive to operate than fossil fuel power plants.
C.
Nuclear power plants can cause thermal pollution in nearby lakes.
D.
Nuclear power plants emit carbon dioxide, sulfur dioxide, and nitrogen oxides which pollute the air.

Solution 1

I think the answer may be d I'm not completely sure

Solution 2

the answer is A. for me

Question

if Brian has 50 apples how many apples does he have now , sorry just needed to change my question

Solution 1

50 bc he HAS 50 so he STILL HAS IT

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