Solution - Career Point

5. A long round conductor of cross-sectional area A ismade of a material whose resistivity depends on theradial distance r from the axis of the conductor as ρα=r 2 , α is a constant. The total resistance per unitlength of the conductor is R and the electric fieldstrength in the conductor due to which a current Iflows in it is E.2πα4πα(A) R =(B) R =22AA2παI4παI(C) E =2A(D) E =2A6. Two infinite plates carry j ampere of current out ofthe age per unit width of the plate as shown. B P andB Q represent magnitude of field at points P and Qrespectively.(A) B P = 0(C) B Q = 0PQ(B) B P = µ 0 j(D) B Q = µ 0 j7. A bar magnet M is allowed to fall towards a fixedconducting ring C. If g is the acceleration due togravity, v is the velocity of the magnet at t = 2 s and sis the distance traveled by it in the same time then,M(A) v > 2g(C) s > 2g3gC(B) v < 2g(D) s < 2g8. In the network shown, the capacitor C is initiallyuncharged. The time constant of the circuit is τ andthe charge on C at time t after the switch S is closedis q.R 3R 1R 2SC9. Binding energy per nucleon vs mass number curvefor nuclei is shown in the figure. W, X, Y and Z arefour nuclei indicated on the curve. The process thatwould release energy is -Binding Energy/Nucleon in MeV8.58.07.55.00(A) Y → 2Z(C) W → 2YZYXW30 60 90 120Mass number of nuclei(B) W → X + Z(D) X → Y + ZSECTION – IIIMatrix - Match TypeThis section contains 2 questions. Each questioncontains statements given in two columns, which haveto be matched. The statements in Column I are labeledA, B, C and D, while the statements in Column II arelabeled p, q, r, s and t. any given statement in Column Ican have correct matching with ONE OR MOREstatements (s) in column II. The appropriate bubbledcorresponding to the answers to these questions have tobe darkened as illustrated in the following example :If the correct matches are A – p, s and t; B – q and r;C – p and q; and D – s and t; then the correctdarkening of bubbles will look like the following.p q r s tABCDppqq10. Capillary rise and shape of droplets on a plate due tosurface tension are shown in column II.Column IColumn II(A) Adhesive forces isrrrss(p)ttAB(A) τ = CR 1CVR 2 −t/ τ(C) q = (1 − e )R + R23⎛ R ⎞(B) τ = C ⎜2R3⎟R 1 +⎝ R 2 + R 3 ⎠CVR 1 −t/ τ(D) q = (1 − e )R + R12greater than cohesive forces(B) Cohesive forces is (q)greater than adhesive forcesABXtraEdge for IIT-JEE 67APRIL 2010