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Alexxx [7]
3 years ago
11

An energy-saving light bulb has an efficiency of 45%. If 5W of light is emitted, what electrical power is required

Physics
1 answer:
Gwar [14]3 years ago
3 0

Answer:

If you're using the bulb as a source of light, then it's. 14/60 = 23.3% efficient.

If you're using it to heat a bird nest or a hamster cage, then it's. 46/60 = 76.7% efficient !

It just depends on your point of view, and what you consider 'useful' output.

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True or false mechanical waves need a medium through which to transport energy
a_sh-v [17]

Answer:True

Explanation: The mechanical waves need a medium through which to transport energy because the perturbation travels inside of the medium so it needs molecules that connect elastically the displacement of the wave. For example the sound mainly uses the air molecules to transport the energy also the sound can be traveled in solid materials like metal rods.

4 0
3 years ago
Read 2 more answers
A force did 80 j of work on an object in 4 m how big was the force
yanalaym [24]

Work = (force) x (distance)

80 J = (force) x (4 m)

Force = (80 J) / (4 m)  =  20 N

That's IF the force was in the same direction as the 4m of motion.
If the force was kind of slanted, then it had to be stronger, and
it had a component of 20N in the direction of the motion.

3 0
3 years ago
A monkey has a bit of a heavy for on the gas pedal. As soon as the light turns green the monkey pushes the gas pedal to the floo
Andrei [34K]

Answer:

s=6.86m/s^2

Explanation:

Hello,

In this case, considering that the acceleration is computed as follows:

a=\frac{v_{final}-v_{initial}}{t}

Whereas the final velocity is 28.82 m/s, the initial one is 0 m/s and the time is 4.2 s. Thus, the acceleration turns out:

a=\frac{28.82m/s-0m/s}{4.2s}\\ \\s=6.86m/s^2

Regards.

3 0
2 years ago
A girl and a boy are riding on a merry go round that is turning at a constant rate. The girl is near the outer edge, and the boy
galina1969 [7]

Answer:

The girl has greater tangential acceleration

Explanation:

The angular acceleration (\alpha) of the merry go round is equal to the rate of the change of the angular velocity, \omega:

\alpha = \frac{d\omega}{dt}

Since all the points of the merry go round complete 1 circle in the same time, the angular velocity of each point of the merry go round is the same, and so all the points also have the same angular acceleration.

The tangential acceleration instead is given by

a_t = \alpha r

where

\alpha is the angular acceleration

r is the distance from the centre of the merry go round

Since the girl is near the outer edge and the boy is closer to the centre, the value of r for the girl is larger than for the boy, so the girl has greater tangential acceleration.

5 0
3 years ago
niobium metal becomes a superconductor when cooled below 9 k. its superconductivity is destroyed when the surface magnetic field
Furkat [3]

Niobium wire with a 2.60 mm diameter has a maximum current capacity of 500 A while still remaining superconducting.

<h3>Describe the present.</h3>

Current is the rate at which charge passes from one point on a circuit to another. In a circuit, a significant current flows when several coulombs or charge pass over the cross section of a wire. When the charge carriers are firmly packed inside the wire, high currents can be generated at low speeds.

<h3>What do current and electron actually mean?</h3>

Electron movement is referred to as electron current. The positive terminal receives electrons that are released by the negative terminal. Traditional current, usually referred to as just current, exhibits behavior consistent with positive charge carriers being the source of current flow. Regular current is received at the positive end and then flows to a negative terminal.

To know more about current visit:
brainly.com/question/15141911

#SPJ4

5 0
9 months ago
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