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What is the function of a 'Repeater' used in communication system?
Concept: Basic Terminology Used in Electronic Communication Systems
"The outward electric flux due to charge +Q is independent of the shape and size of the surface which encloses is." Give two reasons to justify this statement.
Concept: Electric Flux
Distinguish with the help of a suitable diagram, the difference in the behaviour of a conductor and a dielectric placed in an external electric field.
Concept: Dielectrics
Find the equivalent capacitance of the network shown in the figure, when each capacitor is of 1 μF. When the ends X and Y are connected to a 6 V battery, find out (i) the charge and (ii) the energy stored in the network.
Concept: Capacitors and Capacitance
Derive an expression for drift velocity of free electrons.
Concept: Drift of Electrons and the Origin of Resistivity
Distinguish between emf and terminal voltage of a cell.
Concept: Cells, Emf, Internal Resistance
In a meter bridge shown in the figure, the balance point is found to be 40 cm from end A. If a resistance of 10 Ω is connected in series with R, balance point is obtained 60 cm from A. Calculate the values of R and S.
Concept: Metre Bridge: Slide-Wire Bridge
Show variation of resistivity of copper as a function of temperature in a graph.
Concept: Specific Resistance
Explain the term ‘drift velocity’ of electrons in conductor. Hence obtain the expression for the current through a conductor in terms of ‘drift velocity’.
Concept: Drift of Electrons and the Origin of Resistivity
Answer the following question.
A cell of emf E and internal resistance r is connected across a variable resistor R. Plot the shape of graphs showing a variation of terminal voltage V with (i) R and (ii) circuit current I.
Concept: Cells, Emf, Internal Resistance
Obtain the expression for current sensitivity of moving coil galvanometer.
Concept: Moving Coil Galvanometer
Two infinitely long straight parallel wires, '1' and '2', carrying steady currents I1 and I2 in the same direction are separated by a distance d. Obtain the expression for the magnetic field `vecB`due to the wire '1' acting on wire '2'. Hence find out, with the help of a suitable diagram, the magnitude and direction of this force per unit length on wire '2' due to wire '1'. How does the nature of this force changes if the currents are in opposite direction? Use this expression to define the S.I. unit of current.
Concept: Force Between Two Parallel Currents, the Ampere
Increasing the current sensitivity of a galvanometer may not necessarily increase its voltage sensitivity. Explain, giving reason.
Concept: Moving Coil Galvanometer
Define self-inductance of a coil.
Concept: Solenoid and the Toroid - the Solenoid
State how a moving coil galvanometer can be converted into an ammeter.
Concept: Moving Coil Galvanometer
How is current sensitivity increased?
Concept: Moving Coil Galvanometer
In what way is Gauss's law in magnetism different from that used in electrostatics ? Explain briefly.
Concept: Magnetism and Gauss’s Law
The Earth's magnetic field at the Equator is approximately 0.4 G. Estimate the Earth's magnetic dipole moment. Given : Radius of the Earth = 6400 km.
Concept: Current Loop as a Magnetic Dipole: Magnetic Dipole Moment of Current Loop
State Lenz's law. Illustrate, by giving an example, how this law helps in predicting the direction of the current in a loop in the presence of a changing magnetic flux.
Concept: Lenz’s Law and Conservation of Energy
In a given coil of self-inductance of 5 mH, current changes from 4 A to 1 A in 30 ms. Calculate the emf induced in the coil.
Concept: Inductance >> Self Inductance
