Download Syllabus:- Communication System

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Previous Years Questions with Expected Answer/value Points
Syllabus:- Current Electricity
7 Marks
Electric current, flow of electric charges in a metallic conductor, drift velocity, mobility and their
relation with electric current; Ohm’s law, electrical resistance, V-I characteristics (linear and nonlinear), electrical energy and power, electrical resistivity and conductivity. Carbon resistors, colour
code for carbon resistors; series and parallel combinations of resistors; effect of temperature on
resistance.
Emf and potential difference of a cell, internal resistance of a cell, combination of cells in series and in
parallel.
Kirchhoff’s laws and simple applications. Wheatstone bridge, metre bridge. Potentiometer - principle
and its applications to measure potential difference and for comparing emf of two cells; measurement
of internal resistance of a cell
.--------------------------------------------------------------------------------------------------------------------------Q1. A resistance R is connected across a cell of emf ε and internal resistance r. A potentiometer
now measures the potential difference between the terminals of the cell as V. Write the
expression for 'r' in terms of ε, V and R.
1
A1.
Q2. Define the terms (i) drift velocity, (ii) relaxation time. A conductor of length L is connected
to a dc source of emf ε. If this conductor is replaced by another conductor of same material and
same area of cross-section but of length 3L, how will the drift velocity change ?
3
A2.
2
Q3. In the circuit shown, R1 = 4 Ω, R2 = R3 = 15 Ω, R1 = 30 Ω and E = 10 V. Calculate the
equivalent resistance of the circuit and the current in each resistor.
3
A3.
Q4. In the given circuit, assuming point A to be at zero potential, use Kirchhoff's rules to
determine the potential at point B.
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3
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Q5. In the metre bridge experiment, balance point was observed at J with AJ = l. (i) The values
of R and X were doubled and then interchanged. What would be the new position of balance
point ? (ii) If the galvanometer and battery are interchanged at the balance position, how will the
balance point get affected ?
2
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A5.
Q6. Two heating elements of resistances R1 and R2 when operated at a constant supply of
voltage, V, consume powers P 1 and P2 respectively. Deduce the expressions for the power of
their combination when they are, in turn, connected in (i) series and (ii) parallel across the same
voltage supply.
3
4
A6.
Q7.
1
A7.
Q8.
5
3
A8.
OR
6
7
Q9.
1
A9.
Q10.
3
A10.
Q11.
3
8
A11.
Q12.
2
A12.
Q13.
5
9
5
A13.
10
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