Numericals on Current and Dual nature

1)  When a steady current flows through a conductor of non uniform cross section which of the quantities remains constant a) Current b) current density c) electric field d) drift speed

a) we know that I=Q/ t so current is independent of area of cross section

b) current density j= I / A ie current density is inversely proportional to area of cross section

c) electric field E = V / l
E=IR / l
E=(Iρl) /Al

E=Iρ / A so E  is inversely proportional to area of cross section

d) Vd =I / nAe so the drift speed is inversely proportional to area of cross section.

2) The fig shows a plot between 1/√V, where V is the accelarating potential Vs de Broglie wave length λ in the case of two particles having same charge q but different masses m1 and m2 with lines A and B which one will have smaller mass



λ =h/p =h / (√2mK)
λ=h/(√2mqV)
λ=h/(√2mq)×(1/ √V )

(1/ √V )=(√2mq) /h× λ
slope of the given graph is (√2mq  ) /h
slope of A is more so m1>m2
The smaller mass is m2














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