carbon-14 if often used for radioactive dating, but it has its limitations. uranium-238 or lead-206 are most often used to date rocks.

why would u-238 or pb-206 be more useful than c-14 when dating rocks?
a) rocks do not contain any carbon for dating purposes.
b) carbon-14's half-life is much too long to use for dating rocks.
c) the half life of carbon-14 is about 5700 years and is too short date rocks.
d) carbon-14 is only found in living things; it can only be used to date remains.

A1kg cart slams into a stationary 1kg cart at 2 m/s. the carts stick together and move forward at a speed of 1 m/sl. determine whether kinetic energy was conserved in the collision. use the law of conservation of energy to explain the collision

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.

An electric clothes dryer has a resistance of 8 ohms. it draws 30 a of current. what is the voltage, in volts, of the wall outlet that it is plugged into?