physics

posted by .

1. Calculate the de Broglie wavelength in picometers (1 picometer =10^−12 meters) of an electron that has kinetic energy of 10 keV. The mass of an electron is 9.11 x 10^−31 kg

2. Winter is coming, so I want to make a 1500 W heating coil which will plug into a 120 V wall outlet. The coil will have a cross sectional area of 0.01 cm^2 and a length (when fully unwound) of 5 m.

Determine the resistivity of the coil required, in Ωcm:

3. At 300 K we see the electron concentration in the conduction band for pure (undoped) Si is 10^10/cm^3. How many electrons per Si atom is this? You can use scientific notation, as in A.AAeB

Si is diamond cubic with 8 Si atoms per unit cell and a lattice parameter of 0.543 nm.

  • physics -

    help me with plzzz
    Water is a(n) __________ factor in all ecosystems that all living things require.

  • physics -

    important?

  • physics -

    KE=10⁴•1.6•10⁻¹⁹ =1.6•10 ⁻¹⁵J
    KE=mv²/2 =m²v²/2m =p²/2m =>
    p=sqrt(2m•KE)
    λ=h/p =h/sqrt((2m•KE)=
    =6.63•10⁻³⁴/sqrt(2•9.1•10 ⁻³¹•1.6•10 ⁻¹⁵)=
    =1.22•10⁻¹¹ m=0.122 pm
    -------
    R=ρL/A
    P= U²/R= U²A/ ρL
    ρ= U²A/ PL =
    =120²•10⁻²/1500•500=1.92•10⁻⁴Ω•cm

  • physics -

    0.122 is wrong......is that the full answer? are you missing something? the computer says it is wrong.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. de Broglie Wavelength

    The presence of oxygen atoms on the surface results in auger electrons with a kinetic energy of approximately 505 eV. What is the de Broglie wavelength of this electron?
  2. Quantum Physics

    An electron and a proton each have a thermal kinetic energy of 3kBT/2. Calculate the de Broglie wavelength of each particle at a temperature of 2170 K. (kB is Boltzmann's constant, 1.38×10-23 J/K. The mass of the electron is 9.11×10-31 …
  3. physics

    A net force of 1.6×10−15 N acts on an electron over a displacement of 5.0 cm, in the same direction as the net force. (a) What is the change in kinetic energy of the electron in joules?
  4. physics

    i posted this before but no one answered. please help me: A net force of 1.6×10−15 N acts on an electron over a displacement of 5.0 cm, in the same direction as the net force. (a) What is the change in kinetic energy of the …
  5. Physics

    A certain moving electron has a kinetic energy of 1.01 × 10−19 J. Calculate the speed necessary for the electron to have this energy. The mass of an electron is 9.109 × 10−31 kg. Answer in units of m/s.
  6. Physics

    An electron moves on a circular orbit in a uniform magnetic field. The strength of the field is 1.00×10-5 tesla. The kinetic energy of the electron is 178.0 eV. (1 eV = 1 electron volt = 1.6 ×10−19 joules.) Calculate the radius …
  7. physics

    1. Calculate the de Broglie wavelength in picometers (1 picometer =10^−12 meters) of an electron that has kinetic energy of 10 keV. The mass of an electron is 9.11 x 10^−31 kg SOMEONE POSTED: KE=10⁴•1.6•10⁻¹⁹ …
  8. physics

    Calculate the de Broglie wavelength in picometers (1 picometer =10^−12 meters) of an electron that has kinetic energy of 10 keV. The mass of an electron is 9.11 x 10^−31 kg
  9. University Physics II

    1. A voltage of 13 V is applied across the ends of a piece of copper wire 8 cm long. The mass of an electron is 9.11 × 10−31 kg and its charge is 1.6 × 10−19 C. What is the magnitude of the electron’s acceleration?
  10. physics

    A Photon of energy 240 KeV is scattered by a free electron. If the recoil electron has a Kinetic energy of 190 KeV, what is the wavelength of the scattered photon?

More Similar Questions