Answer:
2.295 eV
Explanation:
maximum wavelength, λ = 542 nm = 542 x 10^-9 m
The work function of the metal is defined as the minimum amount of energy falling on the metal so that the photo electrons just ejects the surface of metal.
where, h is the Plank's constant and c be the speed of light
h = 6.634 x 10^-34 Js
c = 3 x 10^8 m/s
Wo = 2.295 eV
Thus, the work function of this metal is 2.295 eV.
The correct answer to the question is B) 5,700 years.
EXPLANATION:
Before going to answer this question, first we have to understand half life period of a radio active substance.
The half life period of a radio active substance is defined as the time in which half of the radio active specimen has undergone decay.
As per the question, the initial concentration of the radioactive carbon-14 is given as 10,000.
Hence, initial concentration .
After 5,700 years, the remaining radio active specimen is 5000. It means that half of the radio active specimen has undergone decay in 5,700 years.
Hence, half life period of the radio active carbon-14 specimen is 5,700 years.