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  1. M

    Magnitude of Magnetic Field

    Homework Statement A rectangular loop of wire is moving toward the bottom of the page with a speed of .042 m/s. The loop is leaving a region in which a magnetic field is directed into the page; the magnetic field outside this region is zero. If during the time of 1.5 s the magnitude of the...
  2. M

    Energy homework problem help

    Homework Statement The atomic mass of gold-197 is 196.96654 u. How much energy is required to completely separate the nucleons in a gold-197 nucleus? Homework Equations E = 196.96654 u x 931.5 The Attempt at a Solution I did the above calculation and got 1.83e5 MeV but im pretty...
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    Proton distance help

    Homework Statement A proton is released from rest at t=o in a uniform electric field whose magnitude is 2.5e-8 N/C. How far has the proton traveled after .5 s? Homework Equations x = vot + 1/2at^2 The Attempt at a Solution x = 1/2(9.81)(.5)^2 = 1.2 but it says the answer is...
  4. M

    Lens Power (diopters)

    Ok cool. Thanks everybody!
  5. M

    Lens Power (diopters)

    ok i still don't completely understand, but I come up with 3.1 ???
  6. M

    Lens Power (diopters)

    I'm still not sure what I'm doing wrong here. Help?
  7. M

    Lens Power (diopters)

    So the only thing I can come up with is .5/.35 = 1.4 (based on what you said)
  8. M

    Lens Power (diopters)

    Homework Statement A middle-aged man starts to wear eyeglasses with lenses of 2.0 D that allow him to read a book held as close as 25 cm. Several years later, he finds that he must hold a book no closer than 35 cm to read it clearly with the same glasses, so he gets new glasses. What is the...
  9. M

    Images on a retina

    Homework Statement Which forms the larger image on the retina of your eye: a 43 ft tree seen from a distance of 210 ft, or a 12 in flower viewed from a distance of 2.0 ft? Homework Equations none? The Attempt at a Solution I don't really understand how you would go about working...
  10. M

    Image Height

    nevermind I found my mistake. thanks for the help though
  11. M

    Image Height

    Homework Statement Your friend is 1.7 m tall. What is the height of her image when she is 4.2 m from you? Homework Equations I used di/do and multiplied that by the height of the friend The Attempt at a Solution I did (4.2/3.5)(1.7) but it was wrong. Not really sure what I'm...
  12. M

    Focal length / Object height

    Ok I'm getting 2 cm. Could you double-check that please?
  13. M

    Index of Refraction

    so would i do 180-110 or something like that? the angle thing is messing me up
  14. M

    Focal length / Object height

    Homework Statement An object is located 27.5 cm from a certain lens. The lens forms a real image that is twice as high as the object. b) Now replace the lens used in Part A with another lens. The new lens is a diverging lens whose focal points are at the same distance from the lens as the...
  15. M

    Index of Refraction

    Homework Statement While studying physics at the library late one night, you notice the image of the desk lamp reflected from the varnished tabletop. When you turn your Polaroid sunglasses sideways, the reflected image disappears. If this occurs when the angle between the incident and...
  16. M

    Light Refraction

    Homework Statement A kitchen has twin side-by-side sinks. One sink is filled with water, the other is empty. 1) Does the sink with water appear to be deeper, shallower, or the same depth as the empty sink? 2) Choose the best explanation from among the following: a) The sink with...
  17. M

    Concave Mirrors

    i got this one already
  18. M

    Convex Mirror / Virtual Image

    i did 1/-9.3 = 1/f - 1/37 (do) then solved for f
  19. M

    Convex Mirror / Virtual Image

    Homework Statement The virtual image produced by a convex mirror is one-quarter the size of the object. b) What is the focal length of this mirror? Homework Equations 1/di = 1/f - 1/do The Attempt at a Solution i found di to be -9.3 cm but when i solved for f i keep getting it...
  20. M

    Plane Mirrors

    thanks! i was close lol
  21. M

    Plane Mirrors

    i got like 1.2m but it said it was wrong.
  22. M

    Magnification/Focal Length

    Ok thanks! as far as magnification, is the formula i provided correct? and how do i figure out if it is inverted or not?
  23. M

    Magnification/Focal Length

    Homework Statement Shaving/makeup mirrors typically have one flat and one concave (magnifying) surface. You find that you can project a magnified image of a lightbulb onto the wall of your bathroom if you hold the mirror 2.0 m from the bulb and 3.7 m from the wall. a) What is the...
  24. M

    Plane Mirrors

    Homework Statement You are 1.9 m tall and stand 3.5 m from a plane mirror that extends vertically upward from the floor. On the floor 1.5 m in front of the mirror is a small table, 0.80 m high. a) What is the minimum height the mirror must have for you to be able to see the top of the...
  25. M

    Concave Mirrors

    i'm sorry, i just have no clue what to do. the whole 3 times larger part is throwing me off
  26. M

    Calculating current

    Homework Statement You want to make a solenoid that is 38 cm long with 4300 turns. How much current should you run through the solenoid to produce a magnetic field of .75 T? Homework Equations B = uoNI The Attempt at a Solution I converted 38 cm to m (not sure where to use this...
  27. M

    Concave Mirrors

    Homework Statement 1)A concave mirror produces a virtual image that is three times as tall as the object. a) If the object is 21 {\rm cm} in front of the mirror, what is the image distance? b) What is the focal length of this mirror? Homework Equations hi/ho di/do 1/f= 1/do...
  28. M

    Frequence of light of galaxy receding from earth

    i reworked it and no clue what im doing wrong. and the answer says it's in fHz
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