Photoelectric effect experiments are performed using three different metal plates p , q and r having work functions φ p = 2.0 eV , φ q = 2.5 eV and φ r = 3.0 eV , respectively. A light beam containing wavelengths of 550 nm , 450 nm and 350 nm with equal intensities illuminates each of the plates. The correct I − V graph for the experiment is

Question

Photoelectric effect experiments are performed using three different metal plates p , q and r having work functions φ p ​ = 2.0 eV , φ q ​ = 2.5 eV and φ r ​ = 3.0 eV , respectively. A light beam containing wavelengths of 550 nm , 450 nm and 350 nm with equal intensities illuminates each of the plates. The correct I − V graph for the experiment is, , , , None of these

MARKS App · Accepted Answer

$ 1. K p ​ = E p ​ − ϕ p ​ = 550 1240 ​ − 20 = 0.2545 eV K q ​ = E q ​ − ϕ q ​ = 450 1240 ​ − 25 = 0.255 eV K r ​ = E r ​ − ϕ r ​ = 350 1240 ​ − 3.0 = 0.543 eV ​ I n t h e ab o v ee q u a t i o n K re p rese n t s ma x im u mkin e t i ce n er g yo f p h o t oe l ec t ro n s an d E , t h ee n er g yo f in c i d e n t r i g h t . F ro m t h e ab o v e v a l u es w ec an see t ha t s t o pp in g p o t e n t ia l , \left|V_r\right|>\left|V_q\right|>\left|V_p\right| F u r t h er , t h e i r in t e n s i t i es a ree q u a l , b u t e n er g yo f in d i v i d u a lp h o t o n o f r i s ma x im u m . He n ce , n u mb ero f p h o t o n s in c i d e n t ( p er u ni t a re a p er u ni tt im e ) o f r c anb e a ss u m e d t o b e l e a s t . He n ce , s a t u r a t i o n c u rre n t o f r s h o u l d b e minim u m . Kee p in g t h ese p o in t s inmin d n oo pt i o n see m s t o b ecorrec t . T h ecorrec t g r a p hi ss h o w nb e l o w , im g src = " h ttp s : // c d n − q u es t i o n − p oo l . g e t ma r k s . a pp / p y q / j e e a ​ d v an ce d / Z ss LL z G j x − o P 96 A T d C 4 k 8 d b e Zq j y a p ​ qS 6 y PBS p f ​ q k . or i g ina l . f u ll s i ze . p n g " > b r > ∴ No choice is correct. $

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