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Light of frequency 9.95×1014Hz ejects electrons from the surface of silver.?
If the maximum kinetic energy of the ejected electrons is 1.70×10−20 J , what is the work function of silver?
2)The work function of gold is 4.58 eV. What frequency of light must be used to eject electrons from a gold surface with a maximum kinetic energy of 6.49×10−19 J ?
3)Radon gas=half-life of 3.82d.What is decay constant
4)a fragment of ancient basket wove from grass.It is determined that the c-14 content of the grass in the basket is 9.4% that of an equal C sample from present-day grass.What age is basket?
5)The no. of radioactive nuclei in particular sample decreases over 14 d to one-sixteenth original no.What is half-life
6)half-life of 158O is 122s
How long does it take for the number of 158O nuclei to decrease to a factor of 2×10−4 of initial value?
1 Answer
- Anonymous2 years ago
That's 6 questions! You will find that if you post one at a time, award Best Answer, then you are more likely to have the others answered if you repeat the process.
Q1.
Photon energy = work function + max.KE of electron
hf = W + K
W = hf - K = (6.63e-34*9.95e14) - 1.70e-20 = 6.43e-19 J
(If you want it in units of eV, divide by 1.60e-19.)