# Search results

1. ### B Is the formation of galaxy groups explained correctly here?

Hello! I watched a video on the Youtube channel Kurzgesagt titled How far can we go? Limits of humanity The video attempts to explain why we may be limited to our local galaxy group even with science fiction technologies. During a part of the video (starting at 2:26), they try to explain how...
2. ### UG EE. Anything valuable I can learn this summer?

Hello. :) I am an undergrad EE student at the end of my fourth semester. I have to take a couple of courses in the summer semester to improve them. So a full time internship might not be possible. Are there any small things I can learn along the way in the summer, on my own? Any new software...
3. ### Logic Design: Interpreting entering and leaving a room.

Homework Statement Hello. We have been given a project in our course "Digital Logic Design", which is an introductory course to Digital Logic. We are only allowed to use gates, multiplexers, flip-flops/latches, counters, comparators, simple displays (like seven segments) etc. I am making...
4. ### Studying Popular science books, science documentaries bad?

I went through someone's thread asking regarding a popular science book, a considerable time ago. I got the impression that the more knowledgeable members in the discussion did not approve of most popular science books (if my memory serves me right the point mainly was that it gave people the...
5. ### Mgh at infinity.

According to the eq. U=mgh the gravitational potential energy should keep increasing with height. But it actually reaches zero at infinity. At what point does the g.p energy start decreasing when going away from earth? Why does this eq. seem to contradict -GMm/r where g.p energy decreases with...
6. ### Range of quadratic equation.

Homework Statement The following equation defines a rational function.Find its Range f(x) = x2/(x-1) The attempt at a solution Let y = x2/(x-1) =>y(x-1) = x2 =>xy-y = x2 =>x2-xy+y = 0 comparing with the general form of quadratic equation ax2+bx+c = 0, a=1, b=-y, c=y...
7. ### Compton effect and Photoelectric effect explained by wave theory?

I have the fifth edition of 'Physics' by Halliday, Resnick and Krane. In the chapter 'The Nature of Light' it is stated that it is possible to explain both photoelectric effect and Compton effect in classical electromagnetic wave theory and this has been known since 1927. It says that...
8. ### Confused about time dilation. (Just got introduced to relativity))

I just got my first official introduction to relativity in my textbook (I'm equivalent to a high school senior student). It is part of a chapter on modern physics.It first mentions the two basic postulates and then briefly introduces what length contraction, time dilation, increase in mass...
9. ### Schools Choosing a good college for B.S physics.

Hello, everyone. What makes an institution better than another for a physics B.S? Faculty, labs or what?
10. ### Position of stellar bodies in space.

Do the sun, moon, earth etc lie in the same plane? I mean are they at the same level or some bodies are above/below others? If yes than why?
11. ### Terminal velocity of spherical body.

In our textbook, the equation for terminal velocity has been derived from Stokes' law and it comes down as follows, vt = (mg)/6(pi)(eta)r (r is the radius of the spherical body) then, by putting the value of 'm' from m=(rho)V [where V = 4/3 * (pi)r3] we get, vt = 2(rho)gr2 / 9...
12. ### Understanding transistors.

I was just curious about trying to understand how transistors work, but didn't understand it properly. http://amasci.com/amateur/transis.html" I found this site through google, which claims that most traditional explanations have contradictions and wrong concepts. And that this simple...
13. ### Help with understanding dual nature of electron.

Hello, I had read about the dual nature of electrons and the quantum numbers for some time ago and was always confused. 1-What does dual nature of electron mean? Does it mean that the electron moves in a sort of wave like motion around the nucleus? Where do the sub-shells and orbitals fit in...
14. ### Why are theories of QM and relativity not possible to combine?

Why are theories of Quantum Mechanics and Relativity not possible to combine? I read this on wikipedia and heard this on a documentary on TV.
15. ### Study methods.

I am just wandering how everyone studies or what good study methods are. My father tells me to read the topics the night before the lecture, then listen to the lecture carefully and then study the topic again after coming home on that day. (I'm in first year of Higher secondary school, K-11...
16. ### Fractional electric charge?

According to the third paragraph over here, http://www.particleadventure.org/quarks.html "Quarks have the unusual characteristic of having a fractional electric charge, unlike the proton and electron, which have integer charges of +1 and -1 respectively." What does the fractional...
17. ### Nature of electromagnetic radiation.

According to wikipedia, "Electromagnetic radiation (often abbreviated E-M radiation or EMR) is a phenomenon that takes the form of self-propagating waves in a vacuum or in matter. It consists of electric and magnetic field components which oscillate in phase perpendicular to each other and...
18. ### What makes a material fissile?

What are the reasons that fissile materials are fissile? What makes them fissile?
19. ### Space as a linen sheet.

In many places (here in forums and on a few documentaries) when talking about relativity, it is often said to consider the space like a piece of cloth,fine net etc. If we think of it that way, shouldn't everything be on the same level in space? And then why do people on South Pole feel gravity...

21. ### Speed of light in denser and rarer medium.

I was studying refraction and as I've heard and read, it occurs due to difference between speed of light in the rarer and denser medium. But isn't speed of light common for all observers? Please don't make fun of me if I've made a stupid mistake somewhere.
22. ### DC doesn't cause electromagnetism?

DC doesn't cause electromagnetism? That is what our teacher says. Can anyone explain why it doesn't? As far I remember I made an electromagnet from a nail by passing current through it from a battery cell about 6 years ago.
23. ### The shape of our solar system's orbits.

What's the shape of the planets orbiting the sun in our solar system according to this website http://www.chacha.com/question/what-is-the-shape-of-orbit-of-planets they are elliptical. But in a documentary (maybe history channel's "The Universe", but I'm not sure) I heard that our solar system...
24. ### Alternating current.

Can someone please explain how the current regularly changes direction after some time in alternating current? I mean if it changes direction, how does it move forward?
25. ### A few general questions.

1-Does an electron and proton ever meet each other if they are attracted to each other? 2-If yes, what happens when they do? 3-Similarly is the earth getting nearer to the sun due to gravity? I know moon is getting away due to some reasons but what about earth and sun.
26. ### Wavelength and penetration.

Why does penetration increase with decrease in wavelength?
27. ### Questions about Quantum state, Pauli exclusion principle and chemistry.

According to this website, http://www.particleadventure.org/pauli.html "At one time, physicists thought that no two particles in the same quantum state could exist in the same place at the same time. This is called the Pauli Exclusion Principle, and it explains why there is chemistry." 1-What...
28. ### Newton's law of gravitation.

What are the problems in Newton's law of universal gravitation? Please explain using simple physics if possible.
29. ### Periodic motion.

According to our textbook "..every periodic motion, however complicated it may be, can always be resolved into simple oscillatory components." Can someone explain this? How can the periodic motion of earth be resolved into oscillatory components?
30. ### Fusion with laser.

How is fusion initiated with a laser? What are the difficulties that are preventing physicists from using it?