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Current Electricity-Important Questions & Preparation Tips

Jun 19, 2013 18:28 IST

    In this article you will get the clue that from where and how the questions are being framed from the chapter Current Electricity
    The experts of jagranjosh.com have full confidence that you will not miss any of the questions in the board exam as well as in competitive exams from this chapter if you will keep the following terms / question in your mind while studying

    • Calculation of average current and instantaneous current from given graph
    • The amount of charge passing through any cross section is given by 2t2+3t+4. Find out current at 4th second and average current for first 4th second
    • Current density is a vector quantity or not
    • Relation of Vrms with temperature while studying conduction through a metal wire
    • What about the average velocity of free electron when there is no any terminal voltage across the wire
    • When average velocity is said as drift velocity(formula also)
    • What is mean free path and on what it depends?
    • Formula of ith electron at a given time t
    • Derivation of formula for drift velocity
    • Calculation of current from fundamental theorem and prove that ohm’s law is only valid for metal if there is no change in physical condition
    • Formula to calculate specific resistance or resistivity mass of electron and relaxation time is given
    • Relation between conductance and specific conductance or conductivity
    • Differential forms of Ohm’s law
    • Formula to calculate the current density and mobility
    • Relation between conductivity and mobility
    • Temperature coefficient of resistivity (α) for metal and semiconductor interms of sign
    • Expression for current in electrolyte having two types charge carrier A+ and B--
    • Relation between  resistance “R” and Temperature coefficient of resistivity “α”
    • Current having magnitude and direction both but it is a scalar quantity. Why?
    •  CGS and SI units of current
    • An electron is revolving in an orbit of radius “r”. By applying Bohr’s theory establish the following relations
    Calculate the current if the speed of electron is “v”
    Relation between magnetic dipole moment and current
    Calculate the angular momentum of electron
    Relation between angular momentum and specific charge
    Relation between magnetic dipole moment and angular momentum
    • Flowing of charge through a conductor is Q=3 – 6t2 .Find the flow of current at t=1 second
    • Flowing of current through a conductor is I= at2- bt . Find the charge associated with the conductor
    • There are four conductor  A,B,C and D whose capacitance and resistance are given below
                   Conductor:          A            B               C             D
                   Capacitance:      30         10         5           2
                   Resistance:        1/30     1/10      1/5        ½
      Identify the best and worst conductor

    • A block having length l, width b and height h. A potential difference of V volt is applies across the length and then across the height. Compare the resistance in both    situations
    • A conductor of length l and radius r. If radius becomes n times of original while length remains constant. Find the new resistance
    • If length of a conductor becomes N times of the initial, then what will be the effect on the area of conductor and also find the new resistance
    • If length of a conductor becomes 1/ N times of the initial, then what will be the effect on the area of conductor and also find the new resistance
    • Calculation power and heat produced in a electrical circuit
    • Application of kirchoff’s law to calculate the voltage and current in a given circuit
    • What forms of energy is converted to electrical energy in an electrochemical cell
    • Combination of resistance and calculation of final resistance specially by applying star delta rule
    • Combination of cells and then calculation of current
    • Concept of emf
    • Calculation of equivalent resistance when N cells are in series and there are  M branches of such series
    • Application of  wheatstone bridge in numerical problems
    • Uses of meter bridge  and on what principle it works
    • In a meter bridge experiment, in determining the resistance of an unknown wire, bridge is balanced at 20cm from one end. If rheostat resistance is 50Ω. Find unknown resistance
    • Dimensional formula of electro motive force, resistance, resistivity and mobility
    • In a potentiometer experiment, the balancing length are 5 Cm and 6 Cm. Find the ratio of their EMF
    • A negligibly small current is passed through a wire of length 15 m and uniform cross-section 6.0 × 10-7 m2, and its resistance is measured to be 5.0 Ω. What is the resistivity of the material at the temperature of the experiment?

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