What is the scenitific notatiin for 0.000326<br>

A solar cell generates a potential difference of 0.25 V when a 550 Ω resistor is connected across it, and a potential difference

Andre45 [30]

a) $400 \Omega$

b) 0.43 V

c) 0.44 %

Explanation:

a)

For a battery with internal resistance, the relationship between emf of the battery and the terminal voltage (the voltage provided) is

$V=E-Ir$ (1)

where

V is the terminal voltage

E is the emf of the battery

I is the current

r is the internal resistance

In this problem, we have two situations:

1) when $R_1=550 \Omega$ , $V_1=0.25 V$

Using Ohm's Law, the current is:

$I_1=\frac{V_1}{R_1}=\frac{0.25}{550}=4.5\cdot 10^{-4} A$

2) when $R_2=1000 \Omega$ , $V_2=0.31 V$

Using Ohm's Law, the current is:

$I_2=\frac{V_2}{R_2}=\frac{0.31}{1000}=3.1\cdot 10^{-4} A$

Now we can rewrite eq.(1) in two forms:

$V_1 = E-I_1 r$

$V_2=E-I_2 r$

And we can solve this system of equations to find r, the internal resistance. We do it by substracting eq.(2) from eq(1), we find:

$V_1-V_2=r(I_2-I_1)\\r=\frac{V_1-V_2}{I_2-I_1}=\frac{0.25-0.31}{3.1\cdot 10^{-4}-4.5\cdot 10^{-4}}=400 \Omega$

b)

To find the electromotive force (emf) of the solar cell, we simply use the equation used in part a)

$V=E-Ir$

where

V is the terminal voltage

E is the emf of the battery

I is the current

r is the internal resistance

Using the first set of data,

$V=0.25 V$ is the voltage

$I=4.5\cdot 10^{-4}A$ is the current

$r=400\Omega$ is the internal resistance

Solving for E,

$E=V+Ir=0.25+(4.5\cdot 10^{-4})(400)=0.43 V$

c)

In this part, we are told that the area of the cell is

$A=4.0 cm^2$

While the intensity of incoming radiation (the energy received per unit area) is

$Int.=5.5 mW/cm^2$

This means that the power of the incoming radiation is:

$P=Int.\cdot A=(5.5)(4.0)=22 mW = 0.022 W$

This is the power in input to the resistor.

The power in output to the resistor can be found by using

$P'=I^2R$

where:

$R=1000 \Omega$ is the resistance of the resistor

$I=3.1\cdot 10^{-4} A$ is the current on the resistor (found in part A)

Susbtituting,

$P'=(3.1\cdot 10^{-4})^2(1000)=9.61\cdot 10^{-5} W$

Therefore, the efficiency of the cell in converting light energy to thermal energy is:

$\epsilon = \frac{P'}{P}\cdot 100 = \frac{9.6\cdot 10^{-5}}{0.022}=0.0044\cdot 100 = 0.44\%$

7 0

2 years ago

A solid cylinder with a mass of 2.72 kg and a radius of 0.083 m starts from rest at a height of 4.20 m and rolls down a 88.7 ◦ s

Bingel [31]

Explanation:

According to the law of conservation of energy ,

Potential energy = kinetic energy

$mgh = \frac{1}{2} \times mv^{2} + \frac{1}{2} \times I \times \omega^{2}$

I = $\frac{mr^{2}}{2}$

$\omega = \frac{v}{r}$

$mgh = [\frac{1}{2} \times mv^{2}] + [\frac{1}{2} \times (\frac{mr^{2}}{2}) \frac{v^{2}}{r^{2}}]$

mgh = $[\frac{1}{2} \times mv^{2}] + [\frac{1}{4} \times mv^{2}]$

$g \times h = \frac{3}{4} \times v^{2}$

$9.8 \times 4.2 = \frac{3}{4} \times v^{2}$

v = 7.4 m/s

thus, we can conclude that the translational speed of the cylinder when it leaves the incline is 7.4 m/s.

5 0

2 years ago

Please, can somebody help me with this project? I'll give brainlest for the best answer! (Do not answer if you don't know or onl

Sauron [17]

The density of the nickel was greater than that of the quarter and penny, thus, the results supports the hypothesis.

<h3>What is density of substance?</h3>

The density of a substance is a measure of how tightly-packed the particles of the substance are.

Density is calculated as the ratio of the mass of the substance and the volume of the substance.

Density = mass/volume

The hypothesis of the lab to compare the densities of a penny, a nickel, and a quarter is:

If the nickel has a greater density than the quarter and penny, then it will have a greater mass to volume ratio. If the nickel has a lower density than the quarter and penny, then it will have a lower mass-to-volume ratio.

The average mass and the average volume of a penny, a nickel, and a quarter are then used to determine the density of each coin.

Based on obtained results, it would be found that the density of the nickel was greater than that of the quarter and penny. Therefore, the results supports the hypothesis.

In conclusion, the density of a substance depends on the mass and the volume.

Learn more about density at: brainly.com/question/1354972

#SPJ1

7 0

1 year ago

A neutral atom of tin (Z = 50) has 69 neutrons. (a) How many protons does it have? (b) What is its mass number?

Olenka [21]

Answer:

Protons = 50

Mass number = 119

Explanation:

A neutral of tin, Sn, has a Z value of 50 and neutrons are 69.

Z is the atomic number. The atomic number is equal to number of protons or number of electrons in an atom that is neutral i.e:

Z = PROTONS = ELECTRONS

So the number of protons = 50 since Z is 50

>>>>>>>>>>>>>>>¦

The bulk of the mass of an atom is concentrated in the nucleus. To calculate mass number, we simply sum all the elementary particles in the nucleus i.e protons and neutrons. These particles are called the nucleons.

Mass number (A) = P + N

= 50 + 69

= 119

3 0

3 years ago

A lorry of mass 4000 kg is travelling at a speed of 4 m/s.

bulgar [2K]

Answer:

KE = 32,000J

v = 8m/s

Explanation:

KE = .5*m*v²

KE = .5*4000kg*(4m/s)²

KE = 32,000J

32,000J = .5*1000kg*v²

v² = 64

v = 8m/s

7 0

2 years ago

What is the scenitific notatiin for 0.000326​

What is the scenitific notatiin for 0.000326