# Excuse me I have Questions

1. Sep 17, 2006

### joori

Excuse me ....I have Questions

Hay members,

1)The intensity reaching the sarface of the Earth from the sun is about 1.36KW1/m^2 .Assuming the Sun to be a sphere(of radius 6.96*10^8m) that radiates like a blackbody , estimate
a) the temperature at its surface and the wavelength of its strongest radiation.
b)the total power radiated by the Sun (the Earth-Sun distance is
(1.5*10^11m)

2)Light of wavelength 350nm is incident on a metallic surface of work function3.9eV.
a)Calculate the kinitic energy of the ejected electrons.
b)Caculate the cutoff frequency of the metal.

3)X-ray of wavelength 0.8nm collide with electrons initially at rest . If the wavelength of the scattered photons is 17nm, determine
a)the kinetic energy of the recoiling electrons
b)the angle at which the photons scatter
c)the angle at which the electrons recoil

4)Consider a tenfold ionized sodium ion,Na10+, which is obtained by removing ten electrons from an Na atom.
a)Calculate the orbiting speed and orbital angular momentum of the electron (with respect to the ion's origin) when the ion is in its fourth excited state.
b)Caculate the frequency of the radiation emitted when the ion deexcites from its fourth excited state to the first excited state.

these are my question I hope some body solve them

2. Sep 17, 2006

### xman

If you want help on these you have to show some work. What have you tried?