1)what are photo-electrons ?
2)an electron of mass 9.4 x 10^-31 kg accelerated through a potential difference,
attained a wavelength of 1.3 x 10-10 m. calculate its velocity.
[h= 6.6 x 10-34 js]

The us government wants to allocate billions of dollars in the next 10 years to assure our future energy security. the funds will be spread among a variety of possible energy resources. where do you think the government should put the greatest support: solar energy, wind energy, clean coal, oil exploration, gas exploration, or a combination of sources? are there other efforts that should be explored? support your position with cited information for both questions.

An athlete is holding 24 lb of weights at a height of 6 inches above the stack as shown. to lower the weights, she applies a constant force of 5 lb to the handle. determine the velocity of the weights immediately before they hit the stack.

Which of the following list the divisions of the geologic time scale in order from longest to shortest