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
fgiga [73]
3 years ago
11

Starting from zero, the electric current takes 2 seconds to reach half its maximum possible value in an RL circuit with a resist

ance R, an inductance L and a battery of emf E. How long will the current take to reach 75% its maximum value (measured from the moment when I = 0)?a. 10 s
b. 8 s
c. 4 s
d. 2 s
e. 1 s
Physics
1 answer:
Leno4ka [110]3 years ago
5 0

Answer:

time=4s

Explanation:

we know that in a RL circuit with a resistance R, an inductance L and a battery of emf E, the current (i) will vary in following fashion

i(t)=\frac{E}{R}(1-e^\frac{-t}{\frac{L}{R}}), where imax=\frac{E}{R}

Given that, at i(2)=\frac{imax}{2} =\frac{E}{2R}

⇒\frac{E}{2R}=\frac{E}{R}(1-e^\frac{-2}{\frac{L}{R}})

⇒\frac{1}{2}=1-e^\frac{-2}{\frac{L}{R}}

⇒\frac{1}{2}=e^\frac{-2}{\frac{L}{R}}

Applying logarithm on both sides,

⇒log(\frac{1}{2})=\frac{-2}{\frac{L}{R}}

⇒log(2)=\frac{2}{\frac{L}{R}}

⇒\frac{L}{R}=\frac{2}{log2}

Now substitute i(t)=\frac{3}{4}imax=\frac{3E}{4R}

⇒\frac{3E}{4R}=\frac{E}{R}(1-e^\frac{-t}{\frac{L}{R}})

⇒\frac{3}{4}=1-e^\frac{-t}{\frac{L}{R}}

⇒\frac{1}{4}=e^\frac{-t}{\frac{L}{R}}

Applying logarithm on both sides,

⇒log(\frac{1}{4})=\frac{-t}{\frac{L}{R}}

⇒log(4)=\frac{t}{\frac{L}{R}}

⇒t=log4\frac{L}{R}

now subs. \frac{L}{R}=\frac{2}{log2}

⇒t=log4\frac{2}{log2}

also log4=log2^{2}=2log2

⇒t=2log2\frac{2}{log2}

⇒t=4

You might be interested in
According to Newton's first law, an object in motion will stay in motion unless:
Nadusha1986 [10]

Answer: unless it's acted upon by an external force

Explanation: Newton first law of motion State that an object will continue in it state of rest or in motion, unless it is been acted upon by an external force

8 0
3 years ago
Please look at the picture included for the question :)
Agata [3.3K]

Answer:

solar to electrical yesssssiiiiirrrrrrrrrr you gonna get it wrong

5 0
3 years ago
Read 2 more answers
1.
Firdavs [7]

1). The forces inside the atom are always, totally, completely, electrostatic forces. Those are so awesomely stronger than the gravitational forces that the gravitational ones are totally ignored, and it doesn't change a thing.

Parts 2 and 3 of this question are here to show us how the forces compare.

Part-2). The electrostatic force between a proton and an electron.

The constant in the formula is 9x10^9, and the elementary charge is 1.602 x 10^-19 Coulomb ... same charge on both particles, but opposite signs.

I worked through it 3 times and got 0.000105 N every time. So the best choice is 'C', even though we disagree by a factor of ten times. You'll see in part-3 that it really doesn't make any difference.

Part-3). Gravitational force between a proton and an electron.

The constant in Newton's gravity formula is 6.67x10^-11 . You'll have to look up the masses of the proton and the electron.

I got 2.163 x 10^-55 N ... exactly choice-C. yay !

Now, after we've slaved over a hot calculator all night, the thing that really amazes us is not only that the electrostatic force is stronger than the gravitational force, but HOW MUCH stronger ... 10^51 TIMES stronger. That's a thousand trillion trillion trillion trillion times stronger !

That's why it has no effect on the measurements if we just forget all about the gravitational forces inside the atom.

4 0
3 years ago
Read 2 more answers
Calculate the speed of a dog running through a yard covering 24m in 52s
makvit [3.9K]

Answer:

0.46 m/s (meters/second)

Explanation:

  • speed = distance/time
  • speed = 24/52
  • speed = 0.461538462 m/s
  • Rounding this, we get speed = 0.46 m/s
5 0
3 years ago
Can A positively charged body attract another positively charged body​
andriy [413]

Like charges repel, unlike charges attract

Two protons will also tend to repel each other because they both have a positive charge. On the other hand, electrons and protons will be attracted to each other because of their unlike charges.

So I would say no, unless the two bodies are placed close to each other where one has much more charge than the other, then due to induction, force of attraction becomes more than the force of repulsion.

3 0
3 years ago
Other questions:
  • The comets in the Oort Cloud may take up to __________________ Earth years to orbit the Sun just once.
    7·1 answer
  • An electron is trapped in a one-dimensional infinite well of width 340 pm and is in its ground state. What are the (a) longest,
    10·1 answer
  • Why the earth is not in thermal equilibrium with the sun ?
    7·2 answers
  • Introduction This section describes the principles and concepts related to the experiment. It is used to help the person reading
    15·1 answer
  • An apple falls straight down from a tree and hits the ground in approximately 0.75 seconds. Based on this information, which is
    5·1 answer
  • Since vectors always have positive magnitudes, the sum of two vectors must have a magnitude greater than the magnitude of either
    11·1 answer
  • What is the energy of work done lifting 2kg mass rocket to a height of 130 m
    8·2 answers
  • An eagle flying at 35 m/s emits a cry whose frequency is 440 Hz. A blackbird is moving in the same direction as the eagle at 10
    11·1 answer
  • Which of the following is NOT an example of convection?
    14·1 answer
  • So I know this is a weird question but if you were to send a piece of paper from the Milky Way to the andromeda galaxy how long
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!