1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
spin [16.1K]
3 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]3 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.
You might be interested in
You are traveling on an interstate highway at the posted speed limit of 70 mph when you see that the traffic in front of you has
vovikov84 [41]

Answer:8.75 s,

136.89 m

Explanation:

Given

Initial velocity=70 mph\approx 31.29 m/s

velocity after 5 s is 30 mph\approx 13.41 m/s

Therefore acceleration during these 5 s

a=\frac{v-u}{t}

a=\frac{13.41-31.29}{5}=-3.576 m/s^2

therefore time required to stop

v=u+at

here v=final velocity =0 m/s

initial velocity =31.29 m/s

0=31.29-3.576\times t

t=\frac{31.29}{3.576}=8.75 s

(b)total distance traveled before stoppage

v^2-u^2=2as

0^2-31.29^2=2\times (-3.576)\cdot s

s=136.89 m

3 0
3 years ago
PLS HEP WILL GIVE BRAINLIEST TO FIRST ANSWER SCIENCEE!!
MAVERICK [17]

Answer:

Claim: The heart pumps more blood throughout the body when one exercises because exercise takes a lot of energy from the body.

Evidence: Heart rate went from 80 bpm to 120 bpm

Reasoning: Doing exercise takes a lot of energy to do, causing the circulatory system to have to work harder and pump more blood throughout the body in order to allow someone to be able to do a task that involves so much movement and energy.

Explanation:

3 0
3 years ago
Which best explains how an object at rest deep in space and far from any massive body behaves compared to an object in free fall
7nadin3 [17]

Answer: They behave the same because, according to the principle of equivalence, the laws of physics work the same in all frames of reference.

Explanation:

According to the equivalence principle postulated by Einstein's Theory of General Relativity, acceleration in space and gravity on Earth have the same effects on objects.

To understand it better, regarding to the equivalence principle, Einstein formulated the following:  

A gravitational force and an acceleration in the opposite direction are equivalent, both have indistinguishable effects.  Because the laws of physics must be accomplished in all frames of reference.

Hence, according to general relativity, gravitational force and acceleration in the opposite direction (an object in free fall, for example) have the same effect.  This makes sense if we deal with gravity not as a mysterious atractive force but as a geometric effect of matter on spacetime that causes its deformation.

3 0
3 years ago
A certain frictionless simple pendulum having a length L and mass M swings with period T. If both L and M are doubled, what is t
vampirchik [111]

The new period is D) √2 T

\texttt{ }

<h3>Further explanation</h3>

Let's recall Elastic Potential Energy and Period of Simple Pendulum formula as follows:

\boxed{E_p = \frac{1}{2}k x^2}

where:

<em>Ep = elastic potential energy ( J )</em>

<em>k = spring constant ( N/m )</em>

<em>x = spring extension ( compression ) ( m )</em>

\texttt{ }

\boxed{T = 2\pi \sqrt{ \frac{L}{g} }}

where:

<em>T = period of simple pendulum ( s )</em>

<em>L = length of pendulum ( m )</em>

<em>g = gravitational acceleration ( m/s² )</em>

Let us now tackle the problem!

\texttt{ }

<u>Given:</u>

initial length of pendulum = L₁ = L

initial mass = M₁ = M

final length of pendulum = L₂ = 2L

final mass = M₂ = 2M

initial period = T₁ = T

<u>Asked:</u>

final period = T₂ = ?

<u>Solution:</u>

T_1 : T_2 = 2\pi \sqrt{ \frac{L_1}{g} }} : 2\pi \sqrt{ \frac{L_2}{g} }}

T_1 : T_2 = \sqrt{L_1} : \sqrt{L_2}

T : T_2 = \sqrt{L} : \sqrt{2L}

T : T_2 = 1 : \sqrt{2}

\boxed {T_2 = \sqrt{2}\ T}

\texttt{ }

<h3>Learn more</h3>
  • Kinetic Energy : brainly.com/question/692781
  • Acceleration : brainly.com/question/2283922
  • The Speed of Car : brainly.com/question/568302
  • Young Modulus : brainly.com/question/9202964
  • Simple Harmonic Motion : brainly.com/question/12069840

\texttt{ }

<h3>Answer details</h3>

Grade: High School

Subject: Physics

Chapter: Elasticity

3 0
3 years ago
Read 2 more answers
What is an earth revolution, what shape is it's path, and how long does it last?
zaharov [31]

An Earth revolution is a trip around the sun in a closed path (relative to the sun).

The path is very nearly an ellipse with the sun at one focus, and a little less nearly a circle with the sun at the center.

One complete revolution takes roughly 365.24 days, and at that point, the Earth immediately begins another one.

We have a special word that we use to refer to that special period of time. In English, it's called a "year".

8 0
3 years ago
Other questions:
  • HOW CAN I SOLVE THIS QUESTION? PLEASE HELP The movement of a locomotive piston in the cylinder is limited to 0.76 m. Assume that
    13·1 answer
  • Jill pulls on a rope to lift a 12 kg pail out of a well, while the clumsy Jack watches. For a 10.0 meter segment of the lift, sh
    14·1 answer
  • 100 points! please help!!!
    12·2 answers
  • A car traveling at 26.8m/s hits the brakes to slow down before turning into a neighborhood. Determine how fast it is going after
    8·1 answer
  • To identify whether the forces are balanced or not, you need to whet
    7·1 answer
  • As you move from left to right across a period the number of valances electrons
    8·2 answers
  • 100 POINTS + BRAINLIEST, HEART, &amp; FIVE STAR.
    8·1 answer
  • What is the area of space around a magnet called?
    5·1 answer
  • The mass of 25cm of ivory was found to be 0.045kg. caculate the density of ivory in SI units​
    9·1 answer
  • A soccer ball is kicked horizontally off a 25 m high cliff and lands at a distance of 40.0 m from the edge of the cliff. Determi
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!