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  1. U

    Balmer Series & Lyman Series

    Q: What are the widths of the wavelength intervals over which (a) the Lyman series and (b) the Balmer series extend? (Each width begins at the longest wavelength and ends at the series limit.) (c) What are the widths of the corresponding frequency intervals? Express the frequency intervals in...
  2. U

    Radioactive Decay

    Q: A 50-g chunk of charcoal is found in the buried remains of an ancient city destroyed by invaders. The carbon-14 activity of the sample is 200 decays/min. Roughly when was the city destroyed? A: I used R = Ro*e^(-lambda*t) and t1/2 = ln2/lambda t1/2 = 3.834*10^-12 s-1 and 200...
  3. U

    Minimum amount of energy necessary to remove a proton from 42-Ca atom

    Q: What is the minimum amount of energy necessary to remove a proton from the nucleus of a 42-Ca atom, thereby converting it into a 41-K atom? The former has a mass of 41.958618 u, the latter 40.961825 u, and the hydrogen atom has a mass of 1.007825 u. My answer: 42-Ca --> 41-K + 1-H...
  4. U

    Frequency of EMR

    Can some please review this question and tell me if the working looks correct? Please advise of any mistakes i may have made. Thanks Q: UV radiation (wavelength = 250 nm) falls on a metal target, and electrons are liberated. If the maximum kinetic energy of these electrons is 1.00*10^-19 J...
  5. U

    Approximate the minimum kinetic energy of an electron

    Q: Approximate the minimum kinetic energy of an electron confined to a region the size of an atom (0.10 nm) How would one go about solving this? What equations/principles are involved and how do we use them? Seems like a simple question but i have no idea where to start? :confused...
  6. U

    Cell Membrane Question

    The membrane of a cell is electrically equivalent to a parallel plate capacitor. A typical cell has a spherical shape with a radius 10 μm and it has a potential of −60 mV with respect to outside. The thickness of the membrane is about 0.01 μm, and it has a dielectric constant of 2. Find: (a)...
  7. U

    Electrical Potential Energy

    I have no idea what principles i am supposed to use in this question? Could someone show me how to do this question please? Thanks :smile: Calculate the electrical potential energy of two protons separated by 1 nm, and compare it with their gravitational potential energy. Estimate how heavy...
  8. U

    Gauss' Law and Flux Question

    I dont really understand Gauss' law - any help with this question would be appreciated? Coaxial cables are made of a copper wire in the center and a concentric cylindrical shell of copper outside, with insulating material in between and outside the shell. The charge per unit length of the...
  9. U

    Blood Transfusion!

    Hi, i dont know how to do this question - some help would be appreciated. Q: A patient is to be given a blood transfusion. The blood is to flow through a tube from a raised flexible bag to a needle inserted in the vein. The inside diameter of the 40mm-long needle is 0.40mm and the required...
  10. U

    Water flowing in a pipe

    I need some help with this question. Q: Poiseuille's equation shows that for laminar flow the volume flow rate through a pipe in proportional to the product of the pressure difference and the fourth power of the radius. The viscosity of water is 1.0*10^-3 Pa.s a) Water in a pipe is flowing...
  11. U

    Ice cube in a glass of water

    Some help with this question please? a) An ice cube floats in a glass of water. When the ice melts, will the water level in the glass rise, fall, or remain unchanged? Justify your answer. b) If the ice had been made from pure water, and the water in the glass was salt water (denser than...
  12. U

    Amplitude of oscillation

    For lunch you and your friends decide to stop at the nearest deli and have a sandwich made fresh for you with 0.300 kg of Italian ham. The slices of ham are weighed on a plate of mass 0.400 kg placed atop a vertical spring of negligible mass and force constant of 200 N/m. The slices of ham are...
  13. U

    Ant on a Tightrope

    A large ant is standing on the middle of a circus tightrope that is stretched with tension (T_s). The rope has mass per unit length (mu). Wanting to shake the ant off the rope, a tightrope walker moves her foot up and down near the end of the tightrope, generating a sinusoidal transverse wave of...
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