Recent content by sheri1987

Homework Statement Calculate the energy and radius for each of the five lowest (n = 1,2,3,4,5) electron orbits in a Helium atom with only one electron. Enter the energy as a positive value in units of "eV" and the radius in units of "nm". Hint: The Helium nucleus has 2 protons so Z = 2 and...

Homework Statement I just want to know if there is a relationship between the ground state of Hydrogen which is 13.6 eV and the ground state of Helium. The problem is asking me to find the ground state of Helium, but I am not sure how to go about it. Any advice? Homework Equations...

Thank you very much!

Optics--Diffraction of Thin Hair Homework Statement A human hair is illuminated with a laser and it produces a diffraction pattern on a screen 1.09 m away. If the distance from the center to the first minimum is 4.8 mm and the wavelength of the laser is 748 nm, what is the thickness of...

Homework Statement The coils in a set of Helmholtz coils have 186 turns and a radius of 15.9 cm. The current is set at 2.2 A. Express your answers in units of "T" for Tesla. a) Calculate the magnetic field along the axis at the center of the two coils (x = 0). b) What is the magnetic...

Homework Statement The moment of inertia for an arm or leg can be expressed as I = amL2, where a is a unitless number that depends on the axis of rotation and the geometry of the limb and L is the distance to the center of mass. Say that a person has arms that are 27.80 cm in length and legs...

Homework Statement The start point of a ballistic launcer is h1 = 18 cm above its launch point (including the correction for the starting angle) and the launch point is h2 = 35 cm above the bench top. A steel ball rolled down the launcher has a mass of 10.2 g. Answer the following question...

Homework Statement A concave mirror (f = 44 cm) produces an image whose distance from the mirror is one-fourth the object distance. (a) Determine the object distance. cm (b) Determine the (positive) image distance. cm Homework Equations 1/do +1/di =1/f do=object...

Relationship of velocity of an electron/velocity of proton to...mass ratio Homework Statement An electron and a proton, starting from rest, are accelerated through an electric potential difference of the same magnitude. In the process, the electron acquires a speed ve, while the proton...

Homework Statement An axon is the relatively long tail-like part of a neuron, or nerve cell. The outer surface of the axon membrane (dielectric constant = 5, thickness = 1 *10-8 m) is charged positively, and the inner portion is charged negatively. Thus, the membrane is a kind of capacitor...

I'm still having trouble...what number needs to be negative?

Homework Statement A metal sphere has a charge of +8.0 µC. What is the net charge after 9.00 *10^13 electrons have been placed on it? Homework Equations q=Ne where q is the charge, N is the number of electrons, and e is given as 1.6*10^-19 The Attempt at a Solution Well...

thank you!

what equation can you solve for time by having speed and distance?

Homework Statement A steel cable, of cross-sectional area 2.79 * 10^-3 m2, is kept under a tension of 1.00 * 10^4 N. The density of steel is 7860 kg/m3 (this is not the linear density). At what speed does a transverse wave move along the cable? Homework Equations velocity =...