HARDMCQ SINGLEJEE Mains ChemistryPhysical ChemistryAtomic StructureIntro
If a certain metal is irradiated with two different light radiations of frequency x and 2x, the maximum kinetic energies of ejected electrons are y and 3y respectively. The threshold frequency of the metal will be
0.x/3
1.x/2
2.3x/2
3.2x/3
Explanation
KE₁: hx − hν₀ = y ...(i). KE₂: h(2x) − hν₀ = 3y ...(ii). From (ii)−2×(i): −hν₀ + 2hν₀ = 3y − 2y = y... Solving (i) and (ii): subtract: hx = 2y → y = hx/2. From (i): hx − hν₀ = hx/2 → hν₀ = hx/2 → ν₀ = x/2.
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