1. C

    Help electrostatics - electric field(beginner level)

    The figure below shows three electric charges q1, q2 and q3 that are located at distances of r1= 2 cm, r2= 2cm and r3= 1cm from the origin of the coordinate system, as shown in the figure. Knowing that θ1 = θ2 = θ3 = 30º, q1=1mC,q2=3mC and q3=-2mC. Consider: 1/4πξº = 9x10 ^ 9 Nm² / C², and...
  2. P

    Manipulating Sound Pressure Level

    I've performed an experiment on guitar tone - ive used a fourier analysis to find the different frequency components. The idea of this is to find the sound pressure level of the consonant intervals present in a guitar tone and compare it to the SPL of the dissonant intervals. I have found the...
  3. S

    Internal energy level configuration of cerium ion doped into a lanthanum fluoride

    Internal energy level configuration of cerium hi, I am a graduate student in my third (research) semester. I am reading an article for four days but not getting this diagram. Can anyone explain this diagram for me?
  4. T

    Physics Resource Textbooks for fundamental physics UG level

    Any suggestions for undergraduate level physics textbooks?
  5. TyrannosaurusWreck

    Sound Level

    Hi guys, I'm back.... So I had this problem: Jane and Sam alternately pound a railroad spike into a tie with their hammers. The crew chief has a migraine, and notes that Jane's hammer blows cause a sound with intensity 5.0 times greater than the sound that Sam makes when he swings his...
  6. C

    Maintaining a certain level of relative humidity

    Hello everyone! I have a practical problem which I have to solve. The problem is the following: We want to maintain constantly a relative humidity of 65% at 10 celsius degrees in a room of 10 square meters territory. To maintain this humidity we have an ultrasonic humidifier which is able...
  7. S

    Can you solve these GCSE level questions?

    i bet you try these gcse level question on your own without looking at the solution. try it u will fail. HD-h-bzvpbs
  8. N

    Lift a hemispherical dome on a level surface filled with water by rotating it

    Hi, I have this problem where I am asked to find out which angular velocity I need to have to lift this 30 tons heavy dome with a hole on the top. I have attached a sketch and how I tried to solve it, but i get the wrong answer. Right answer is 1,95 rad/s. Thanks
  9. J

    A level help

    Hiya Was wandering if anyone could explain the following: n+ p - k+ x Deduce the relative charge, baryon number and strangeness of particle x ? Thanks
  10. J

    A practical method to turn the planet Earth. Is there a physics level flaw in this?

    Studying the Earth-Moon tidal force it occurred that energy from the system (moon) could be used to apply an external force (non-Earth reference frame) to turn the Earth. By affixing a horizontal lever (eg. 100m long) onto the ocean floor or an island mass, and attaching a large plate...
  11. T

    Just thinking - Beginning Level Idea...

    Acceleration (of a BODY, say) is often a "given" in HS physics text problems. "Givens" are called "initial conditions," (e.g., physical information supposedly known at the initial instance of observance of the event of some BODY.) Trusting we are. We suppose the author correctly saw (or...
  12. S

    constant level oiler

    How does a constant level oiler work supplying a pump system via a gravity fed reservoir? How does the pump maintain a constant level of oil in its reservoir? Is it because when its full it has a pressure exterted which the gravity fed oiler cannot overcome.
  13. M

    Ball rolling on level surface with friction

    So you roll a ball on a level surface with friction. Once you let go, it rolls on its own without slipping, left to right.5 Neglect air resistance and rolling friction. Static friction on the ball at the contact point acts backwards to the left, tending to slow it down I would guess. At the same...
  14. G

    Why does the Fermi level of an insulator fall within the band gap?

    "Fermi level" is the term used to describe the top of the collection of electron energy levels at absolute zero temperature. Why does the Fermi level of an insulator fall within the band gap? There is no energy level in the band gap. See also here
  15. W

    Sea Level

    New to the forum. Don't know where to post this question. If liquids "seek a level", how can there be reports of sea levels rising at various specific points along coasts? Setting aside variations in levels due to temperature of the water, do not the levels of all inter-connected bodies of...
  16. B

    Friction question for which there isn't a forum level low enough.

    Hello all, I have a couple of question about friction that I can't get my head round. They're very elementary. If someone could help me understand them I'd be very grateful thank you. Here they are: A student is pushing a box across a rough floor. Friction acts between the box and the floor...
  17. T

    A Level Basic Refraction Help

    Hi guys, wondering if anyone can help me on this specific questions? Assume refractive index of air = 1 Speed of light in air = 3x10^8 ms Question 9c: Cheers guys really appreciate it!!
  18. B

    Nuclear energy and sea level rise

    The world's nuclear electrical capacity in the year 2000 was 350 GWe. If all the waste heat from operating these nuclear plants for one year were used to melt ice (initially @ 0 deg celsius) from the Antarctic ice cap, what would be the increase in the depth of oceans? Assume that 70% of the...
  19. M

    Sound intensity level

    A sound wave is measured to have a 20-decibel sound intensity level (SIL). And the sound wave power flux (measured in Watts/m2) is then increased by a factor of 2000. What is the new sound level (in decibels) after this factor of 2000 increase in sound power? I figured that 20 db = I but...
  20. S

    can a hydrogen atom have an electron spin number in the 2p energy level?

    can someone please also give me more information on the fourth quantum number? I'm failing to understand wikipedia's description