Light of wavelength 200.0 nm is incident on a metal plate with a threshold wavelength of 400.0 nm. what is the energy of the incident photon in electron volts?
a.
2.48 × 105 ev
c.
6.20 ev
b.
0.161 ev
d.
3.10 ev

Acalorimeter is to be calibrated: 51.203 g of water at 55.2 degree c is added to a calorimeter containing 49.783 g of water at 23.5c. after stirring and waiting for the system to equilibrate, the final temperature reached is 37.6 degree c. specific heat capacity of water (s = 4.18 j/g∙degree c). calculate the calorimeter constant. (smδt)warm water = -[(smδt)cold water + (calorimeterδtcold water)]