Subject

Physics

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

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 Multiple Choice QuestionsShort Answer Type

1.

Does the charge given to a metallic sphere depend on whether it is hollow or solid? Give a reason for your answer.

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2.

A long straight current carrying wire passes normally through the centre of the circular loop. If the current through the wire increases, will the be an induced emf in the loop? Justify

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3.

At a place, the horizontal component of earth's magnetic field is B and angle of dip are 60o. What is the value of a horizontal component of the earth's magnetic field at the equator?


4.

How is the speed of em-waves in vacuum determined by the electric and magnetic field?

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5.

How does Ampere-Maxwell law explain the flow of current through a capacitor when it is being charged by a battery? Write the expression for the displacement current in terms of the rate of change of electric flux. 

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6.

(i) Find the value of the phase difference between the current and the voltage in the series LCR circuit shown below. Which one leads in phase: current or voltage?

(ii) Without making any other change, find the value of the additional capacitor C, to be connected in parallel with the capacitor C, in order to make the power factor of the circuit unity.

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7.

A resistance of R draws current from a potentiometer. The potentiometer wire, AB, has a total resistance of Ro. A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of potentiometer wire.




When the slide is in the middle of the potentiometer, only half of its total resistance i.e. R0/2 (since resistance is directly proportional to length) will be between A and point of contact (C), say R1, will be given by the following expression.


The total resistance between A and B will be sum of the resistance between A & C and C&B i.e R1+R0/2
Current flowing through the potentiometer will be


The voltage V1 taken from the potentiometer will be the product of current I and the resistance R1


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8.

(i) Find equivalent capacitance between A and B in the combination given below. Each capacitor is of 2μF capacitance.

(ii) If a dc source of 7 V is connected across AB, how much charge is drawn from the source and what is the energy stored in the network?

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9.

Drive the expression for electric field at a point on the equatorial line of an electric dipole.

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10.

Depict the orientation of the dipole in (i) stable, (ii) unstable equilibrium in a uniform electric field.

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