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spin [16.1K]
2 years ago
14

A lightbulb has an effciency of 8.2%. How much light energy (not heat energy) is generated by the bulb every second if the buld

has pwer of 21w?
Physics
1 answer:
telo118 [61]2 years ago
8 0
It really depends on what the bulb is being used for, since efficiency means how much of the output is USEFUL.
If the bulb is being used for light in a dark room, then it produces (8.2% x 21W) = 1.72 joules per second of light energy.
If the bulb is being used to keep a hamster cage or a fish tank warm, then the 8.2% is the useful part, and the light is the other (91.8% x 21W) = 19.28 joules per second.
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Monochromatic light of wavelength 687 nm is incident on a narrow slit. On a screen 1.65 m away, the distance between the second
Sophie [7]

Answer:

a ) 1.267 radian

b ) 1.084 10⁻³ mm

Explanation:

Distance of screen D = 1.65 m

Width of slit d = ?

Wave length of light   λ  = 687 nm.

Distance of second minimum fro centre y = 2.09 cm

Angle of diffraction = y / D

=  2.09 /1.65  

= 1.267. radian

Angle of diffraction of second minimum

= 2 λ / d

so 2 λ / d = 1.267

d = 2 λ / 1.267 = (2 x 687 ) /1.267 nm

=1084.45 nm = 1.084 x 10⁻³ mm.

3 0
2 years ago
What do these letters stand for<br> P=mv
victus00 [196]

Answer:

The equation for momentum of a piece of matter.

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Explanation:

Hope This Helps

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4 0
2 years ago
A horizontal force of 200 N is applied to move a 55 kg television set across a 10 m level surface. What is the work done by the
vivado [14]

Answer:

The work done is "2000 J".

Explanation:

The given values are:

Force,

F = 200 N

Mass,

m = 55 kg

Displacement,

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Now,

The work done will be:

⇒  Work \ done= Force\times displacement

On substituting the given values, we get

⇒                     =200\times 10

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3 0
3 years ago
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Lisa [10]

Answer:

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7 0
2 years ago
How does potential and kinetic energy change in to each other and back again?
PolarNik [594]
They can change because the law of conservation of energy allows it to happen, for example when you are sitting, your body is at a potential energy state, meaning you are inert, you are not moving, but when you get up and suddenly start walking or running, that energy is converted to kinetic energy, meaning that you are moving and can be changed back into potential energy if all of a sudden you stop running or walking to rest or sit down. This is just an example of how energy can are transferred multiple ways
6 0
3 years ago
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