Question 369: Dual Nature of Matter and Radiation

Question

In a photoemission experiment, the maximum kinetic energies of photoelectrons from metals P, Q and R are E
P
, E
Q
and E
R
, respectively, and they are related by E
P
= 2E
Q
= 2E
R
. In this experiment, the same source of monochromatic light is used for metals P and Q while a different source of monochromatic light is used for the metal R. The work functions for metals P, Q and R are 4.0 eV, 4.5 eV and 5.5 eV, respectively. The energy of the incident photon used for metal R, in eV, is ___________.

Accepted Answer

E
P
= 2E
Q
= 2E
R
= E(assume)
For metal P and Q,
E
1
- 4 = E
P
= E Ã¢ÂÂ¦Ã¢ÂÂ¦..(1)
E
1
- 4.5 = E
A
= E/2 Ã¢ÂÂ¦Ã¢ÂÂ¦..(2)
Subtracting equation (2) from (1), we get
E/2 = 0.5
For metal R
E
2
- 5.5 = E
R
= E/2 = 0.5
$$ \Rightarrow $$ E
2
= 6

Dual Nature of Matter and Radiation

Integer / Numeric Answer Type