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Q1. Derive the equations for balance in the case ofmaxwells inductance capacitance bridge.

Draw the phasor diagram for balance condition.

OR

Q1. Describe the working of Heaviside Mutual Inductance Bridge for determination mutualinductance of a coil. Explain how the self inductance of a coil can be determined with the

help of a mutual inductance. Also explain how the use of a balancing coil helps in

elimination of errors on account of resistance of leads etc.

Q2. Describe how an unknown capacitance can be measured with the help of D Sautys

bridge. What are the limitation of this bridge and how are they overcome by using a

modified form of D sautys bridge? Draw phasor diagram to illustrate your answer.

OR

Q2. Describe the substitution method of measurement of medium resistance. List the factoron which the accuracy on the method depends.

Q3. Draw the circuit of a Wheatstone bridge and derive condition of balance.

OR

Q3. Draw the circuit of a Kelvins Double Bridge used for measurement of low resistance.

Derive the condition of balance.

Q4. Attempt all the questions. Each carry equal marks.

(i) Maxwell s inductance capacitance bridges is used for measurement of inductanceof:

(a)Low q coils (c) high q coils(b)Medium q coils (d) low and medium q coils

(ii) In D sauty s bridge(unmodified form) it is :(a)Possible to obtain balance even if both the capacitors are imperfect(b) Possible to obtain balance if one of the capacitors is perfect(c)Possible to obtain balance only if both the capacitors are perfect(d)All of the above

(iii) Wagner s Earth Devices are used in a.c. bridge circuit for :(a)Eliminating the effect of earth capacitances(b)Eliminating the effect of inter compound fields(c)Eliminating the effect stray electrostatic fields(d)Shielding the bridge elements.

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(iv) A Wheatstone bridge cannot be used for precision measurements because errors areintroduced into on account of

(a)Resistance of connecting leads (c) thermo-electric emfs(b)Contact resistance (d) all of the above

(v) High resistances are provided with a guard terminal. This guard terminal is used to:(a)Bypass the leakage current(b)Guard the resistance against stray electrostatic field(c)Guard the resistance against overloads(d)None of the above

(vi) From the point of view of safety, the resistance of ear thing electrode should be(a) low(b)

high

(c)medium(d)the value of resistance of earth electrodes does not affect the safety.

(vii) A potentiometer is basically a:(a)Deflectional type instrument(b)Null type instrument(c)Deflectional as well as null type instrument(d)A digital instrument

(viii) Standardization of potentiometer is done in order that, they becomes(a)accurate

(b) precise

(c) accurate and direct reading

(d)accurate and precise