8. Ella wants to replace old bulbs of her home with new LED bulbs. She buys LED bulb that has inbuilt AC to DC converter of output 5V and 2.5A. a. If the LED is 75% efficient, what would be the power dissipated? b. Find the work done by the LED when it is connected to the power supply and left for 1hour 15 minutes.​

Answers

Answer 1

The power dissipated by the LED is 20 Watts and the work done for 1 hour 15 minutes is 56.25 kJ.

What is electrical power?

Electrical power is the rate at which electrical work is done.

Electrical power = voltage × current

The LED is 75% efficient means that 75% of power dissipated by the LED is converted to light.

Total power dissipated = 5 × 2.5 = 12.5 Watts

Work done = power × time (in seconds)

Work done = 12.5 × (1 × 3600 + 15 × 60)

Work done = 56250 J = 56.25 kJ

Therefore, the power dissipated by the LED is 20 Watts and the work done for 1 hour 15 minutes is 56.25 kJ.

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Related Questions

3. Two wires increase in length by the same amount when both their temperatures increase by the same amount, as shown in the diagram. Before the temperature increase, the longer wire is 1.2525 m long. The shorter wire’s linear coefficient of thermal expansion is 1.135 times that of the longer wire. How much shorter is the shorter wire before the temperature increase? Answer to three significant figures
Viết cho Ngọc Khánh

Answers

Two wires increase in length by the same amount when both their temperatures increase by the same amount, the shortness of the wire before the temperature increase is mathematically given as

dL=0.1485m

How much shorter is the shorter wire before the temperature increase?

Generally, the equation for change in length is mathematically given as

[tex]dl=lo \alpha dt[/tex]

Therefore

dl1=dl2

Where

a2=1.35a1

Hence

a1l1dt= a2l2dt

a1(1.2525)= a1*(1.135)(l2)

L2=1.104m

In conclusion, a change in length due to temperature is

dL=1.2525-1.104m

dL=0.1485m

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?How much work is done by 5 kg water as it is evaporated at 10 bar pressure​

Answers

Answer:

The (latent) heat of vaporization (∆Hvap) also known as the enthalpy of vaporization or evaporation, is the amount of energy (enthalpy) that must be added to a liquid substance, to transform a given quantity of the substance into a gas.

The enthalpy of vaporization is a function of the pressure at which that transformation takes place. The heat of vaporization diminishes with increasing temperature and it vanishes completely at a certain point called the critical temperature (Critical temperature for water: 373.946 °C  or 705.103 °F,  Critical pressure: 220.6 bar = 22.06 MPa  = 3200 psi ).

You want to lift a heavy box with a mass L = 56.0 kg using the two-ideal pulley system as shown. With what minimum force do you have to pull down on the rope in order to lift the box at a constant velocity? One pulley is attached to the ceiling and one to the box.

Answers

The minimum force required to lift the box at constant velocity is determined as 274.4 N.

Minimum force required

The minimum force required to lift the box at constant velocity is the tension in one of the pulleys, and the magnitude is calculated as follows;

2T = mg

where;

m is mass of the boxT is the minimum force required

2T = mg

T = mg/2

T = (56 x 9.8)/2

T = 274.4 N

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The radius of a nucleus is about 1/10000 that of an atom.

Calculate the radius of a magnesium nucleus.
Give your answer in standard form.

Answers

The radius of a magnesium atom is 0.160nm. The radius of a nucleus is about 1/10000 that of an atom.

What is nucleus?

The nucleus is an organelle that contains the DNA i.e. genetic material and other materials which is required for cellular processes. It is only found in eukaryotic cells that is responsible for controlling the processes of the cell.

So we can conclude that the radius of a magnesium atom is 0.160nm which is equals to about 1/10000 radius of that atom.

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A rocket is fired with an initial velocity of 100m/s at an angle of 550 above the horizontal. It explodes on the mountain side 12s after its firing. What is the x-and y- coordinates of the rocket relative to its firing point?​

Answers

The rocket's x- and y-coordinates relative to its launching point will be -0.975 and -0.219 m/sec, respectively.

What is velocity?

The change of displacement with respect to time is defined as the velocity.  Velocity is a vector quantity. it is a time-based component.

Velocity at any angle is resolved to get its component of x and y-direction.

Given data;

V = 100m/s

θ=550°

t= 142 sec

The given velocity is resolved into the component as:

[tex]\rm V_X=Vcos \theta \\\\ V_y = Vsin\theta[/tex]

The x coordinate of the rocket:

[tex]\rm V_x = 100 cos \ 550^0 \\\\ V_x = -0.975616[/tex]

The y coordinate of the rocket:

[tex]\rm V_y =100 sin \ 550^0 \\\\ V_y = -0.219484[/tex]

Hence, the x-and y- coordinates of the rocket relative to its firing point will be -0.975 and -0.219 m/sec.

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the frequency of a pendulum has a period of 1.13 seconds is?

A) 0.88
B) 1.13
C) 1.27
D) 11.3

Answers

Answer:

A 0.88

Explanation:

frequency=1/period

=1/1.13=0.88

when solving for t you used sin theta instead of cos theta?

Answers

Looking out from a vertex with angle θ, sin(θ) is the ratio of the opposite side to the hypotenuse , while cos(θ) is the ratio of the adjacent side to the hypotenuse . No matter the size of the triangle, the values of sin(θ) and cos(θ) are the same for a given θ, as illustrated below.

Mark as brainlest answer!

What is the meaning of the safety symbol shown below?

Answers

Answer:

D. Poison

Explanation:

Explain four different types of fitness technologies that are used to help improve your fitness level.

Answers

Answer: endurance, strength, balance, flexibility

Explanation:

walking, jogging, swimming, biking

In the video, the students create two charged tapes, a "pointy" tape and a "square" tape. The pointy tape is first placed on top of the square tape, and the two are pulled apart. After pulling them apart, the students observed the behavior of the tapes when they were brought near each other, but not touching each other.

Answers

The two pointy tapes repel. This shows they have the same type of charge.

Attraction of two charges

The attraction of two charges occurs when the two charges have opposite charges.

Repulsion of two charges

The repulsion of two charges occurs when the two charges have similar charges.

Thus, since the two pointy tapes will have the same charge, we can conclude that they will repel each other when brought near each other.

The complete question is below:

How did the pointy tapes behave when brought near each other, and what does this demonstrate about their charges?

Two pointy tapes repel. This shows they have opposite types of charge.

Two pointy tapes attract. This shows they have opposite types of charge.    

Two pointy tapes repel. This shows they have the same type of charge.

Two pointy tapes attract. This shows they have the same type of charge.

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a body covers a distance of 20 m in 2 second and then covers 40 metre in next it s8 on a straight line calculate its velocity​

Answers

Answer:

6 m/s

Explanation:

Average velocity = Total distance covered / Time taken to cover distance

Finding Average Velocity :

⇒ 20 m + 40 m / 2 s + 8 s

⇒ 60 m / 10 s

6 m/s

Velocity

a body covers a distance of 20 m in 2 second and then covers 40 metre in next it s8 on a straight line calculate its velocity.

Solution:

AV = 20m + 40m/s 2s + 8secondAV = 60m/s ÷ 10sAV = 6m/s²

So the Average velocity is 6m/s²

2069 (Set B) Q. No. 9d How much force is required to punch a hole 1 cm in diameter in a steel sheet 5mm thick whose shearing strength is 2.76 × 108 Nm 2. X [4]​

Answers

The force required to punch a hole 1 cm in diameter in a steel sheet is 0.176 x 10¹³ N.

What is force?

The force is defined as the shear stress or pressure applied per unit area.

F = P/A

Given is a steel sheet whose thickness t = 5mm = 5x 10⁻³ m, shearing strength P = 2.76 × 10⁸ N/m², diameter of hole d = 1cm = 1x 10⁻² m

The area to be punched A = πd xt

A = π x 1x 10⁻² x5x 10⁻³

A = 15.7 x 10⁻⁵ m²

The force required to punch a hole is

F = 2.76 × 10⁸ /  15.7 x 10⁻⁵

F = 0.176 x 10¹³ N.

Thus, the punching force is  0.176 x 10¹³ N.

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One of the possible criteria of Schizophrenia is hallucinations.
Select one:
O True
O False

Answers

It is true but that’s not Physics

What is tan for the given triangle?

Answers

Answer:

tan is 15 for that triangle

Answer:

c. 1.33

Explanation:

edmentum

Why would you expect a person with impairment of the organs of equilibrium to become more unsteady when the eyes are closed?

Answers

Answer:

A person with impairment of organs of equilibrium would compensate for their lack of sensory information by their eyes therefore if their eyes are closed they aren't able to sense their location in space accurately (Proprioception)

Explanation:

what is difference between heat engine and carnot engine

Answers

Answer: A heat engine uses temperature differences which cause pressure changes to exert force on a moving part. A Carnot Process is a theoretical explanation of a process involving pressure and temperature changes during ,amongst other things, phase changes.

Explanation:

Answer: The difference is a heat engine uses temperature differences which cause pressure changes to exert force on a moving part, A Carnot engine is only a theoretical explanation of a process involving pressure and temperature changes during or amongst other things.

Explanation:

Fluid Dynamics links the concept of viscosity to the fluid flow. Mention how the contact angle, surface tension, capillarity governs the flow?

Answers

Fluid Dynamics is an area of ​​research that started a long time ago, along with Calculus. It combines techniques of Mathematical Analysis and of Dynamical Systems, such as Bifurcation Theory, among others.

What is surface tension?

Surface Tension is a phenomenon that occurs in all liquids, it is characterized by the formation of a kind of elastic membrane at its ends.

How to calculate the contact angle?

Contact angles in powders can be measured using the sessile drop measurement in the compressed powder or using the force tensiometer with the Washburn method.

In fluid dynamics, the variables of surface tension, viscosity and contact angle are treated. When dealing with viscosity we have  fluid can be viscous or a real fluid. In general, fluids are viscous.

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Electromagnets show the interaction of

a. electric current and electric
charges

b. electric charges and magnetic
dipoles

c. magnetic fields and iron filings

d. magnetic fields and electric
currents

Answers

Answer:

B

Explanation:

Electric charges and magnetic dipoles

PLEASE RESPOND I NEED FAST THANK YOU GIVING LOTS OF POINTS WILL GIVE BRAINLIEST

Answers

#1

The kinetic energy decreases

#2

This is because of law of conservation of linear momentum .

The momentum is conserved

So the velocity of ball decreases than before .

So kinetic energy also decreases

#3 and #4

Kinetic energy of the can increases as after the collision the velocity of the can increases so the kinetic energy also increases

what is dipersion of light

Answers

Answer:

The separation of visible light into its different colors is known as dispersion. It was mentioned in the Light and Color unit that each color is characteristic of a distinct wave frequency; and different frequencies of light waves will bend varying amounts upon passage through a prism

Explanation:

The mass of a piece of gold is 57 g and its volume is 3 cm³. What is its
density?
A 15 g/cm³
B. 54 g/cm³
C. 14 g/cm³
OD. 19 g/cm³

Answers

Using the formula of density, mass/volume
57/3 = 19g/cm^3

The answer is D

Calculate the work done by a force of 30 N in lifting a load of 2 kg to a height of 10 m (g = 10 m/s2)

F=mg
F= 2 (kg) × 10 (m/s2) = 20 N
W= Fd = mgh
W= 20 × 10 = 200 J

Guys, please answer. If the relationship gives a product of 20 N, why is 30 N in the question?​

Answers

Answer:

300 J

Explanation:

Given :

Applied force = 30 NMass = 2 kgHeight = 10 mg = 10 m/s²

Work done by the force :

Work done = Force x DisplacementWork done = mg x hWork done = 30 N x 10 mWork done = 300 J

Note :

What you have calculated is the work done by gravitational force on the object (that too, incorrectly)But in the end, it asks for work done by the force of 30NHence, the given answer ~


An object has an initial velocity of 15 m/s and a constant acceleration of 4 m/s2. How long will it take before its final velocity is equal to three times its initial velocity?

Answers

Based on the calculations, it would take 7.5 seconds before the final velocity of this object would be equal to three times its initial velocity.

Given the following data:

Initial velocity = 15 m/s.Constant acceleration = 4 m/s².Final velocity = 3 × 15 = 45 m/s.

How to calculate the acceleration of an object?

Mathematically, acceleration can be calculated by using the first equation of motion:

v = u + at

Where:  

v is the final velocity.u is the initial velocity.t is the time measured in seconds.

Making t the subject of formula, we have:

t = (v - u)/a

Substituting the given parameters into the formula, we have:

t = (45 - 15)/4

t = 30/4

t = 7.5 seconds.

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A lamp with a resistance of 60 Ohms is plugged into a 110-Volt household circuit. How much current flows through the lamp?

Answers

The current flowing through the lamp is  1.833A

What is current?

The current is the stream of charges which flow inside the conductors when connected across the end of voltage.

From the Ohm's law, V =IR

Here, R is the proportionality constant called resistance of the resistor

A lamp with a resistance of 60 Ohms is plugged into a 110-Volt household circuit.

I = V/R

Put the values, we get

I = 110/60

I = 1.833A

Thus, the current flowing through the lamp is  1.833A

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Calculate the amount of energy needed to boil away 1.6 L of water that initially has a temperature of 55 °C.

Answers

The amount of energy needed to boil away the water at the initial temperature  is 301,248 J.

Energy required to boil the water

The amount of energy needed to boil the water at the given is calculated as follows;

Q = mcΔθ

where;

m is mass of water

density of water = 1000 g/L

mass = density x volume

mass of water = 1000 g/L x 1.6 L = 1,600 g

Q = 1600 g x 4.184 J/g⁰C x (100⁰C - 55 ⁰C)

Q = 301,248 J

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Iron is attracted to magnets and rusts when in the presence of oxygen. Which is true about these properties of iron?

Answers

Iron forms an oxide when exposed to air is a true property about this element.

What is Iron?

This is an element which has magnetic properties and forms an oxide when exposed to air.

Iron forms ferric oxide in the presence of oxygen which is the brown like color seen in the form of rust.

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Define 1 volt. Express it in terms of SI unit of work and charge calculate the amount of energy consumed in carrying a charge of 1 coulomb through a battery of 3 V.​

Answers

Answer:

Work done =3 joules

Explanation:

1 volt is the same as 1 Coulomb and 1 Joule

V=W/Q

1=W/3

W=3 x 1

W=3 Joules

Swamps and other wetlands do not offer much value to humans. True or false?

The subject for this question is science (I'm not sure if science is called physics or chemistry)

Answers

The statement 'Swamps and other wetlands do not offer much value to humans' is FALSE.

What are Swamps?

Swamps and other wetlands are specific ecosystems that are abundant in biodiversity and therefore offer many advantages.

Biodiversity is fundamental to discovering new biotechnological applications and therefore swamps are fundamental for humans.

In conclusion, The statement 'Swamps and other wetlands do not offer much value to humans' is FALSE.

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Cells are made up of molecules. Why then do we say that a structural unit of a living organism is a cell and not a molecule?

Answers

Answer:

Because molecules cannot function independently whereas when they combine they give rise to functional unit called cell.

The chemical symbol for the element carbon ‘ aluminum hydrogen ‘oxygen and sodium

Answers

ANSWER:

C = carbon

Al = aluminium

H = hydrogen

O = oxygen

Na = sodium

I hope it helps u dear (^^)

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