The work function of a metal surface is 4.80 × 10-19 j. the maximum speed of the electrons emitted from the surface is va = 7.7 × 105 m/s when the wavelength of the light is λa. however, a maximum speed of vb = 5.1 × 105 m/s is observed when the wavelength is λb. find the wavelengths λa and λb.

Asatellite that goes around the earth once every 24 hours iscalled a geosynchronous satellite. if a geosynchronoussatellite is in an equatorial orbit, its position appearsstationary with respect to a ground station, and it is known as ageostationary satellite find the radius rof the orbit of a geosynchronous satellite that circles the earth.(note that ris measured from the center of the earth, not the surface.) you mayuse the following constants: the universal gravitational constant g is 6.67 \times 10^{-11}\; {\rm n \; m^2 / kg^2}. the mass of the earth is 5.98 \times 10^{24}\; {\rm kg}. the radius of the earth is 6.38 \times 10^{6}\; {\rm m}.