# IIT JEE Advanced & Mains Physics 2018 : Electricity : Rankfile / expected questions III

IIT JEE Advanced & Mains Physics 2018 : Electricity : Rank file / expected questions / Physicsmynd Elite Series  /  Page  III

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19]  A cone [ of resistivity ] is cut off at a height of h from it’s base.If it’s uniformly charged throughout it’s  cross-sections, then the resistance between the two end of the cut – off cone is – A ] B ] C ] D] 20 ] A charge distribution produces an electric field where c is a constant. Then the total charge in the distribution is –

A ] B ] C ] D ] 21 ] Figure below shows the path of an electron where A B – when not under the influence of a field and B’ , C’ and D’ ,under the influence of three different electric fields 1 , 2 ,and 3 respectively . . Then the Drift Velocity of the electron under the second field is indicated by – A ] AB + AB’

B ] ABB’

D ] BC’

22 ] Earnshaw’s law states that a collection of point charges cannot be maintained in a stable stationary equilibrium configuration solely by the electrostatic interaction of the charges .Give a simple non-mathematical proof for the same .

23 ] Two conductors are embedded in a material of conductivity and dielectric constant . The resistance between the two conductors is found to be . Find the magnitude of the capacitance between the two conductors .

24] Figure below shows an hypothetical infinite conducting plane in the ( x,y,z) plane having charges Q1 , Q2 , Q3 , Q4  located in cavities.What can we predict with certainty regarding the nth cavity containing charge Qn ? A ] V experienced by Q1 will influence the V of Qn

B ] V  of Q1  = V of Qn

C ] The whole conducting surface up to that containing Qn is an equipotential .

D ] V of the conducting plane cannot be zero .

25 ] Parallel to ( x ) and at a distance d .above a grounded conducting plane ( xy ) is placed an infinite wire of uniform charge Then the  potential in the region above the plane is –

A ] V   = B ] V   = C ] V   = D ] V   = 26 ]  In the above case,the charge density induced on the conducting plane is –

A } B ] C ] D ] 27 ] Diagram below represents a hollow conductor on which a test potential of around 90,000 V is applied.Choose the graph which correctly represents the incidence of potential inside the cavity . The x axis denotes the time elapsed in pico -seconds .  