Please answer !!!A company wants to install a sensor to monitor the light level in the offices of their buildings. The sensor contains an LDR which has a resistance of 10kohlms in daylight and 100kohlms in the dark . The choice of resistor in the circuit is between one of 25kohlms and 1 megaohlm. The input p.d to the sensing circuit of 12 v . State and explain which resistor is the best choice for the circuit in light and dark which each of the resistors . You could put your calculations in a table .

Answers

Answer 1

Answer:

Explanation:

The sensor contains an LDR which has a resistance of 10kohlms in daylight and 100kohlms in the dark.

If the resistor in the circuit is 1 megaohlm, the total resistance in daylight and darkness will be 1.01 megaohms and 1.1 megaohlms.

The percentage difference = (1.1-1.01)/1.1*100% = 8.18%

If the resistor in the circuit is 25 kohlm, the total resistance in daylight and darkness will be 35 kohms and 125 kohlms.

The percentage difference = (125-35)/125*100% = 72%

With the input p.d to the sensing circuit fixed at 12 v, the sensing current will change according to the total resistance. A 72% difference is much more detectable. So the 25 kohm resistor is the better choice.

Answer 2

Answer:

Explanation:

V=IR

I=12/(R of resistor + R of LDR)

R of LDR = 10kohm in light and = 100kohm in dark

R1 =  25kohm

R2 = 1Mohm

solve 4 current

                       light                                       dark

R1        12/(25+10)=0.343mA          12/(25+100)=0.096mA

R2       12/(1000+10)=0.012mA       12/(1000+100)=0.011mA

so R1 is better as its easier 2 tell its light or dark


Related Questions

A sled with mass 11.00 kg moves in a straight line on a frictionless horizontal surface. At one point in its path, its speed is 4.00 m/s; after it has traveled a distance 3.00 m beyond this point, its speed is 7.00 m/s. Use the work-energy theorem to find the force acting on the sled, assuming that this force is constant and that it acts in the direction of the sled's motion.

Answers

Answer:

The magnitude of the force acting on the sled is 60.5 newtons.

Explanation:

The Work-Energy Theorem states that the work done by the external force applied on the sled ([tex]W[/tex]), in joules, is equal to the change of its translational kinetic energy ([tex]\Delta K[/tex]), in joules:

[tex]W = \Delta K[/tex] (1)

By definitions of work and translational kinetic energy we expand the equation above:

[tex]F\cdot s = \frac{1}{2}\cdot m\cdot (v_{2}^{2}-v_{1}^{2})[/tex] (1b)

Where:

[tex]F[/tex] - External force applied on the sled, in newtons.

[tex]s[/tex] - Travelled distance, in meters.

[tex]v_{1}, v_{2}[/tex] - Initial and final velocities, in meters per second.

If we know that [tex]m = 11\,kg[/tex], [tex]v_{1} = 4\,\frac{m}{s}[/tex], [tex]v_{2} = 7\,\frac{m}{s}[/tex] and [tex]s = 3\,m[/tex], then the external force applied on the sled is:

[tex]F = \frac{m\cdot (v_{2}^{2}-v_{1}^{2})}{2\cdot s}[/tex]

[tex]F = \frac{(11\,kg)\cdot \left[\left(7\,\frac{m}{s} \right)^{2}-\left(4\,\frac{m}{s} \right)^{2}\right]}{2\cdot (3\,m)}[/tex]

[tex]F = 60.5\,N[/tex]

The magnitude of the force acting on the sled is 60.5 newtons.

An elevator of 3 × 10^4N is raised to a height of 100m in 20s . The work done by electric motor is equivalent to?​

Answers

Answer:

there it is fella tried on ma own observation

What is kinetic and potential energy?

Answers

Answer:

the energy produced in a body due to its motion is kinetic energy.

energy produced in a body due to its position is potential energy.

Explanation:

kinetic energy is the energy possessed by a body in motion

Potential energy is the energy possessed by a body by virtue of its position with respect to a reference level

The unit of area is a derived unit. Why?

Answers

Explanation:

area=length(m) ×breadth(m) . The unit of area is expressed in terms of fundamental units m^2.thus it is derived unit

The dependent variable measured was the ______
a. fan speed
b. mass
c. acceleration

Answers

Answer:

a

Explanation:

Fan speed is the answer

Brass is made by melting a mixture which contain 67% by mass of copper and 33% by mass of zinc if no change in volume.Calculate the density of brass​

Answers

Answer:

The density of brass is approximately 8,261.73 kg/m³

Explanation:

The percentage composition by mass of brass is given as follows;

The percentage by mass of copper = 67%

The percentage by mass of zinc = 33%

The density of copper, ρ₁ = 8.96 g/cm³

The density of zinc, ρ₂ = 7.133 g/cm³

Therefore, where we have, m = 100 g of brass, we have;

The mass of copper, m₁ = 67 g

The volume of copper, V₁ = m₁/ρ₁

∴ V₁ = 67 g/(8.96 g/cm³) ≈ 7.47767857 cm³

The volume of zinc, V₂ = m₂/ρ₂

∴ V₂ = 33 g/(7.133 g/cm³) ≈ 4.62638411 cm³

The volume of the brass, V = V₁ + V₂

V = 7.47767857 cm³ + 4.62638411 cm³ ≈ 12.104 cm³

The density of brass, ρ = m/V

∴ ρ = 100 g/(12.104 cm³) ≈ 8.26 g/cm³

The density of brass, ρ ≈ 8.26 g/cm³ = 8,261.73 kg/m³

DO U KNOW CARRYMINATI

Answers

Answer: Yes, I know



Explaination: Rough words and roaster

Please help!!!!! I will give brainliest. Describe four examples of acceleration you see during your day. Choose an object that is slowing down, one that is speeding up, one that is moving at a constant speed but changing direction, and one that is moving at a constant velocity with zero acceleration.

Answers

When the brake is applied to the car and comes to rest after some time is an example of an object that is slowing down.

What is acceleration?

The rate of change of velocity with respect to time is known as acceleration. According to Newton's second law, the eventual effect of all forces applied to a body is its acceleration.

1. When the brake is applied to the body and comes to rest after some time is an example of an object that is slowing down.

2. When a person accelerates the car and the velocity is increasing is an example of speeding up.

3. An object moves in a circular motion moving at a constant speed but changing direction,

4. Acceleration is the rate of change of velocity. If the change in the velocity is constant the acceleration is zero is an example of moving at a constant velocity with zero acceleration.

To learn more about acceleration, refer to the link;

https://brainly.com/question/2437624

#SPJ1

used to measure temperature
used to measure force
prefix that means 1/100
prefix that means 1,000
prefix that means 1/1,000

Answers

Answer:

prefix that means 1/100 = Centi

prefix that means 1,000 = Kilo

prefix that means 1/1000 = Milli

Explanation:

Behaviors in deer such as herding and male deer using antlers to compete for females increase the chances of successful reproduction.

True or False

Answers

Answer:

True

Explanation:

The reproductive success of any species is the capability to produce their offspring per breeding lifetime or event.

Most of the species have to attract their partners by their physical capability and build up so that the mother can choose her partner in order to breed the best kind of off spring.

In the context, in case of deer, the size of the their antlers as well as behavior in herding is considered as the best chances for a successful reproduction to compete among the males and find their breeding mate.

Thus the answer is TRUE.

Una prenda de 320gramos de ropa gira en el interior de una lavadora si dicha lavadora tiene 40 cm y gira con una frecuencia de 4 hz halla el periodo la velocidad angular la fuerza con la que gira la prenda y la velocidad lineal de la lavadora

Answers

Answer:

Período del tambor: [tex]T = 0.25\,s[/tex], fuerza sobre la prenda: [tex]F \approx 80.852\,N[/tex], velocidad lineal del tambor: [tex]v \approx 10.053\,\frac{m}{s}[/tex], velocidad angular del tambor: [tex]\omega \approx 25.133\,\frac{rad}{s}[/tex].

Explanation:

La expresión tiene un error por omisión, su forma correcta queda descrita a continuación:

"Una prenda de 320 gramos de ropa gira en el interior de una lavadora si dicha lavadora tiene un radio de 40 centímetros y gira con una frecuencia de 4 hertz. Halle a) el período, b) la velocidad angular, c) la fuerza con la que gira la prenda y d) la velocidad lineal de la lavadora."

El tambor gira a velocidad angular constante ([tex]\omega[/tex]), en radianes por segundo, lo cual significa que la prenda experimenta una aceleración centrífuga ([tex]a[/tex]), en metros por segundo al cuadrado. En primer lugar, calculamos el período de rotación del tambor ([tex]T[/tex]), en segundos:

[tex]T = \frac{1}{f}[/tex] (1)

Donde [tex]f[/tex] es la frecuencia, en hertz.

([tex]f = 4\,hz[/tex])

[tex]T = \frac{1}{4\,hz}[/tex]

[tex]T = 0.25\,s[/tex]

Ahora determinamos la fuerza aplicada sobre la prenda ([tex]F[/tex]), en newtons:

[tex]F = m\cdot a[/tex] (2)

[tex]F = \frac{4\pi^{2}\cdot m \cdot r}{T^{2}}[/tex] (2b)

Donde:

[tex]m[/tex] - Masa de la prenda, en kilogramos.

[tex]r[/tex] - Radio interior del tambor, en metros.

([tex]m = 0.32\,kg[/tex], [tex]r = 0.4\,m[/tex], [tex]T = 0.25\,s[/tex])

[tex]F = \frac{4\pi^{2}\cdot (0.32\,kg)\cdot (0.4\,m)}{(0.25\,s)^{2}}[/tex]

[tex]F \approx 80.852\,N[/tex]

La velocidad lineal de la lavadora es:

[tex]v = \frac{2\pi\cdot r}{T}[/tex] (3)

([tex]r = 0.4\,m[/tex], [tex]T = 0.25\,s[/tex])

[tex]v = \frac{2\pi\cdot (0.4\,m)}{0.25\,s}[/tex]

[tex]v \approx 10.053\,\frac{m}{s}[/tex]

Y la velocidad angular del tambor de la lavadora:

[tex]\omega = \frac{2\pi}{T}[/tex]

([tex]T = 0.25\,s[/tex])

[tex]\omega = \frac{2\pi}{0.25\,s}[/tex]

[tex]\omega \approx 25.133\,\frac{rad}{s}[/tex]

which of the following items has the most inertia while at rest

Answers

Answer:

wats the following items

when a car drives in a circle there must be ?

Answers

no net force axting on it

Answer:

I think none of above

Explanation:

hioe it's right answer

What is an example of a series circuit

Answers

Answer:

Explanation

The most famous and common example is Christmas tree lights. You can't tell easily by looking at them whether they are in series or parallel. But you sure know the difference when one of them burns out. When that happens, the whole string goes dead. No matter what you do (other than find out which bulb burned out) will not fix the problem.

Another example is anything that is temperature controlled. For example a furnace is controlled by a thermostat. When the room temperature reaches a certain point, the thermostat is constructed in a certain way so that it forms an open circuit and no current can flow through it. The furnace motor turns off and the furnace stops pumping hot air into a room.

Which statement describes how chemical formulas, such as H20, represent compounds?

Answers

Answer:

They show the elements that make up a compound.

They show the three-dimensional shape of a molecule.

They show the types of atoms that make up a molecule.

They show the number of each type of atom in a molecule.

Explanation:

❣️(◍Jess bregoli◍)❣️

#keep learning!!

Why is a person not a good blackbody radiator?
O A. A person emits only visible light.
OB. A person emits only infrared radiation.
O C. A person absorbs most of the light that hits him or her.
O D. A person reflects little of the light that hits him or her.

Answers

Answer:

O C. A person absorbs most of the light that hits him or her.

Explanation:

Answer:

Option D hope it's helpful mark me as brainlist

A 75.0 kg man pushes backward on a 300.0 kg boat with a force of 150.0N causing the boat to accelerate backward at 0.5m/s^2. What is the acceleration of the man?

A) 150.0 m/s^2
B) 8.00 m/s^2
C) 2.00 m/s^2
D) 4.00 m/s^2

Answers

Answer:

C) 2.00 m/s^2

Explanation:

F = m*a

150N = 75kg(a)

a = 150N/75kg

a = 2.0m/s²

Help me please Ima give brainiest

Answers

Sand. You can identify tiny sugar crystals.


Answer: vinegar

A heterogeneous mixture is a mixture in which the composition is not uniform throughout the mixture. ... A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead, form two separate layers. Each of the layers is called a phase.

Hope it helps...

A partially inflated balloon is faded over the open end of a glass beaker that contains water the beaker is placed in an ice bath which cause the water and causes the balloon to the flea what are the correct designs for the heat and work changes to the beaker and balloon system

Answers

Answer:

a

Explanation:

HELPPP ILL GIVE BRAINLIST

Answers

Answer:

1= Kidneys

2= Ureters

3=Bladders

4=Urethra

Explanation:

Functions of kidney: Regulations of water balances, excretions of nitrogenous wastes(urea)

Functions of Liver: Detoxifications, protein synthesis

Functions of Skin: Temperature regulations, Metabolic functions, Excretion

Functions of lungs: Respiration, Water balance regulations

Tip: If you want faster and correct answers you should label your questions under the correct subject.

A cell has an emf of 1.5 V and an internal resistance of 0.65 Q.
The cell is connected to a resistor R.
[0[8].[4] State what is meant by an emf of 1.5 V.
[2 marks]
I
[0] 8]-[2] The current in the circuit is 0.31 A.
Show that the total power output of the cell is approximately 0.47 W.
[1 mark]
[o[s).[3] Calcutate the energy dissipated per second in resistor R.
[2 marks]
energy dissipated per second = Ist
[o[si.[4] The cell stores 14 kJ of energy when it is fully charged. The cell's emf and internal resistance are constant as the cell f discharged.
Calculate the maximum time during which the fully-charged cell can deliver energy to
resistor R.
[2 marks)
maximum time = 5

Answers

Answer:

14000 J / 0.40 J/s = 35 000 s or about 9.75 hrs

Which of these is untrue about ray diagrams?
A. The arrowheads show the direction of the light

B. Lines must always be straight

C. More arrowheads on lines mean a brighter light

Answers

Answer:

The untrue option is C: "More arrowheads on lines mean a brighter light"

Explanation:

Ray diagrams are used to show how the light behaves with things like mirrors or lenses. Where we only study how the direction of the light changes when it interacts with these objects.

The "light" is represented with arrows, where again, the only thing we care is the direction of the light, so the first statement is true, the arrowheads show the direction of the light, and only that.

The intensity of the light, in this context, has no effect on how light behaves, so there is not a necessity of representing the intensity of the light, thus, more arrowheads on lines do not mean a brighter light. It may only be used to represent changes in direction of the light.

Finally, we know that light travels in straight pats (the pats can be curved in some cases, like with large gravitational fields, but this is not the case of a ray diagram) so the lines that represent the light should always be straight, thus option B is also true.

The untrue option is C: "More arrowheads on lines mean a brighter light"

If a serve hits the net, what happens?

• Re-do
• Dead Ball
• Other teams point
• Play the ball

Answers

Answer:

Depends: Is it tennis or volleyball?

Explanation:

If it's volleyball, it's C, the other teams point.

If it's tennis, it's A, you get a re-do.

If the amplitude of a sound wave is increased by a factor of four,how does the energy carry by the sound wave in each time interval change?

Answers

Answer:

The energy will be increased by a factor 16

Explanation:

Mathematically, we have it that the energy carried by the sound wave is directly proportional to the square of the amplitude

So we have it that;

E = k * A^2

where E is the wave energy

K is the constant value

A is the amplitude value

So;

If E1 = k * (A1)^2

E2 = k * (A2)^2

But A2 = 4A1

E2 = k * (4A1)^2

E2 = k * 16(A1)^2

Divide E2 by E1

E2/E1 = k/k * 16(A1)^2/(A1)^2

E2/E1 = 16

E2 = 16 * E1

so simply, the energy will be increased by a factor of 16

Change the following as indicated in the brackets.
8m (km,cm)​

Answers

metres to kilometres = 1/1000

8 m ⇒ 0.008 km

metres to centimetres = × 100

8 m ⇒ 800 cm

Answer:

1000m=1km

so, 8m=8/1000 = 0.008km

1m=100cm

so, 8m=8×100=800

Two parallel circular rings of radius R have their centres in the X axis separated by a distance L. If each ring carries a uniformly distributed charge Q,find the electric field at points along the X axis

Answers

Answer:

E" =  Q/4πε₀√[(x² + R²)]³(x - (L - x)/√[(L - 2x)L/(x² + R²) + 1]³})

Explanation:

The electric field due to a charged ring of radius R at a distance x from the center of the ring when the axis of the ring is located on the x - axis is

E = Qx/4πε₀[√(x² + R²)]³

Since the rings are separated by a distance L, the electric field at point x due to the second ring is E' = -Q(L - x)/4πε₀[√((L - x)² + R²)]³. It is negative since it points in the negative x - direction.

So, the resultant electric field at x is E" = E + E' = Qx/4πε₀[√(x² + R²)]³ + {-Q(L - x)/4πε₀[√((L - x)² + R²)]³}

E" =  Qx/4πε₀√[(x² + R²)]³ - Q(L - x)/4πε₀√[((L - x)² + R²)]³

E" =  Q/4πε₀(x/√[(x² + R²)]³ - (L - x)/√[((L - x)² + R²)]³})

E" =  Q/4πε₀(x/√[(x² + R²)]³ - (L - x)/√[(L² - 2Lx + x² + R²)]³})

E" =  Q/4πε₀(x/√[(x² + R²)]³ - (L - x)/√[(L - 2x)L + (x² + R²)]³})

E" =  Q/4πε₀√[(x² + R²)]³(x - (L - x)/√[(L - 2x)L/(x² + R²) + 1]³})

So, the electric field at points along the x axis is

E" =  Q/4πε₀√[(x² + R²)]³(x - {(L - x)/√[(L - 2x)L/(x² + R²) + 1]³})

Which nutrients are needed in soil in larger doses?
Mineral Nutrients

Macronutrients

Non-mineral Nutrients

Micronutrients

Answers

Answer:

The primary nutrients are nitrogen, phosphorus and potassium.

The intermediate nutrients are sulfur, magnesium, and calcium.

The remaining essential elements are the micronutrients and are required in very small quantities.

Answer:

The primary nutrients are nitrogen, phosphorus and potassium.

The intermediate nutrients are sulfur, magnesium, and calcium.

The remaining essential elements are the micronutrients and are required in very small quantities.

Explanation:

A student starts at position (4,4) m and undergoes three displacements:
d1 = (2, -3) m, d2 = (-5, 0) m, and d3 = (1, 6) m.
What is the final position of the student? Show your solution graphically and numerically.
please help!!

Answers

Answer:

The final position is  (2, 7)m

Explanation:

When we work with coordinate pairs, the addition works as:

(a, b) + (c, d) = (a + c, b + d)

So, for example, if we start at (a, b), and we have a displacement d = (1, 1)

we just need to solve:

(a, b) + (1, 1) = (a + 1, b + 1)

Now, in this case, we start at (4, 4)m

first, we have d1 = (2, -3) m

After this displacement, the position is:

(4, 4)m + (2, -3)m = (4 + 2, 4 - 3)m = (6, 1)m

Now we have a displacement d2 = (-5, 0) m

After this, the position is:

(6, 1)m + (-5, 0)m = (6 -5, 1 + 0)m = (1, 1)m

After this, we have the final displacement d3 = (1, 6) m, so the final position will be:

(1, 1)m + (1, 6)m = (1 + 1, 1 + 6)m = (2, 7)m

Below you can see a rough sketch of the path that the student take, where he/she starts at point A.

ASAPP PLS HELP MEE
The density of aluminum is 2.7 g/cm^3. Which of the following statement is true?

A) 1 g of aluminium has a volume of 1 cm^3

B) 2.7 g of aluminium has a volume of 1 cm^3

C) 1 g of aluminium has a volume of 2.7 cm^3

D) 2 g of aluminium has a volume of 7 cm^3​

Answers

Answer:

B) 2.7 g of aluminium has a volume of 1 cm^3

Explanation:

Density can be defined as mass all over the volume of an object.

Simply stated, density is mass per unit volume of an object.

Mathematically, density is given by the equation;

[tex]Density = \frac{mass}{volume}[/tex]

If the density of aluminum is 2.7 g/cm³, it simply means that 2.7 g of aluminium has a volume of 1 cm³

Check:

Given the following data;

Mass = 2.7 grams

Volume = 1 cm³

Substituting into the formula, we have;

[tex]Density = \frac{2.7}{1}[/tex]

Density = 2.7 g/cm³

QUESTION 30 A tennis ball moves back and forth 10 times in 5 sec. The frequency of its motion is​

Answers

Answer:

so in 1 sec 2 times

so frequency = 2

Explanation:

Other Questions
which unit would be most suitable for its scale?A mmBcrn?Dcm[0625_504_9p_1].8A piece of cotton is measured between two points on a ruler.1cotonBAS2456789101112131415 16when the lenge of coton is wound closely around a pen, goes round six times.pensix turns of coton-What is the distance onde round the pen?4 2.2 mB 26 cm13.2 cmD 15.6 cm Select all lines that apply. Which details best express the theme that it is important to stay focused on one's dreams? He Had His Dream by Paul Laurence Dunbar He had his dream, and all through life, Worked up to it through toil and strife. Afloat fore'er before his eyes, It colored for him all his skies: The storm-cloud dark Above his bark The calm and listless vault of blue Took on its hopeful hue, It tinctured every passing beam- He had his dream. He labored hard and failed at last, His sails too weak to bear the blast, The raging tempests tore away And sent his beating bark astray. But what cared he For wind or sea! He said, "The tempest will be short, My bark will come to port." He saw through every cloud a gleam- He had his dream.A. He had his dream, and all through life, Worked up to it through toil and strife.B. The storm-cloud dark Above his barkC. He had his dream. He labored hard and failed at last, His sails too weak to bear the blastD. He said, "The tempest will be short, My bark will come to port." He saw through every cloud a gleam fake anwsers will be reportedWhat role did the country of Portugal play during the Age of Exploration? Why was it important during that time period? Help me with this question too The formula below gives the area of a semi-circle, A, with a radius of r.Solve the formula for the radius PLS PAK I ANSWER NITO KAILANGAN LANGPO Three Bell ringing constituency in intervals of 30,36 and 45 minutes respectively. At what time will they ring together again if they ring simultaneously at 8:00 a.M. At midday the temperature in Moscow was 7C.At midnight it was -3C.By how many degrees did the temperature fall? You are a farmer who is putting away bales of hay for the winter months. Each bale is 3 feet long, 2 feet wide, and 1.5feet thick. The bales of hay are stacked in storage bins 12 feet long, 8 feet wide, and 6 feet deep.What is the minimum number of bins needed for 350 bales of hay? Which of the following may have influenced neumatic notation?A. Byzantine chant notationB. Muslim chant notationC. Hindu chant notationD. Ancient Roman music If the distance from D to D' is 10 and the distance from A to D is 2 what is the scale factor? Zebra Company sells a segment of its operations at a loss. Zebra has not previously experienced such an event and does not expect to again. The loss from the disposal of the segment should be reported in the income statement as: Select one: A. A separate amount in comprehensive income B. A separate amount in net income from continuing operations C. A separate amount in a discontinued operations section D. As part of cost of goods sold 6. Roll a pair of dice. What is the probability that a total of 12 will be face up? Evaluate f(3)A. 18B. 12C. 4D. 21 The quadratic function y = -x2 + 10x - 8 models the height of a trestle on a bridge. The x-axis represents ground level.To find where the section of the bridge meets ground level, solve 0 = -x2 + 10x - 8.Where does this section of the bridge meet ground level? What is a name for the marked angle?Chose 1 answer Drag the tiles to the correct boxes to complete the pairs.Match the mRNA sequences to their DNA sequences.AUUACGCAUCCGAAAUGUGAUCAUUACUUUUUAACGAAAAATTGCarrowRightGGCTTTACAarrowRightTAATGCGTAarrowRightCTAGTAATGarrowRight HELP PLEASEEEEEEEEEEEEEEEEEEEEE Al igual que la Constitucin de los Estados Unidos, Roma tenia un conjunto de leyes escritas que se conocan como: Based on the article "Will the real atomic model please stand up?," why did J.J. Thomson experiment with cathode ray tubes?