Depict the direction of the magnetic field lines due to a circular current carrying loop?

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1. Depict the direction of the magnetic field lines
   due to a circular current carrying loop?
2. How would a biconvex lens appear when placed in a
   trough of liquid having the same refractive index
   as that of the lens?
3. What is the difference between an n-type and an
   p-type intrinsic semiconductor?
4. Define intensity of radiation in photon picture
   of light?

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• 5. Why is the classical (Rutherford) model for an
  atom of electron orbitting around the nucleus
  not able to explain the atomic structure?
• 6. What is the function of a repeater used in
  communication system?
• 7. Distinguish between a dielectric and a
  conductor?
• 8. When an ac source is connected across an ideal
  inductor, show on a graph the nature of variation
  of the voltage and the current over one complete
  cycle?

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• 9. A battery of emf 10 V and internal resistance
  3 O is connected to a resistor. If the current in
  the circuit is 0.5 A, find
• The resistance of the resistor.
• The terminal voltage of the battery.
• 10. A carrier wave of peak voltage 12 V is used
  to transmit a message signal. Calculate the peak
  voltage of the modulating signal in order to have
  a modulation index of 75.

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• 11. A proton and a deuteron, each moving with
• velocity enter simultaneously in the
  region on
• magnetic field B acting normal to the
  direction of
• velocity. Trace their trajectories
  establishing the
• relationship between the two.
• 12. A lamp is connected in series with a
  capacitor.
• Predict your observation when this
  combination
• is connected in turn across
• ac source and
• a dc battery. What change would you notice in
  
• each case if the capacitance of capacitor is
  
• increased?

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13. (a) Identify the boxes, P and Q in the
block diagram of a receiver shown in
the figure. (b) Write the function
of the blocks P and Q
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14. Determine the potential difference across
the plates of the capacitor C of the
network shown in the figure. Assume E2
gt E1 15. A particle of mass 10-3 kg and
charges 5 µC enters into a uniform electric
field of 2 X 105 NC-1, moving with a
velocity of 20 ms-1 in a direction opposite
to that of the field. Calculate the
distance it would travel before coming to rest.

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16. (a) How does a diamagnetic material behave
when it is cooled to very low
temperatures? (b) why does a paramagnetic
sample display greater magnetisation
when cooled? Explain. 17. State two
conditions required for obtaining
coherent sources? In youngs arrangement
to produce interference pattern, show that
dark and bright fringes appearing on the
screen are equally spaced .
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18. (a) Plane and convex mirrors are known to
produce virtual image of the objects.
Draw a ray diagram to show how, in the case
of convex mirrors, virtual objects can
produce real images. (b) Why are
convex mirrors used as side view mirrors
in vehicles? (or)
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A fish in a water tank sees the outside world
as if it ( the fish) is at the vertex of
a cone such that the circular base of the cone
coincides with the surface of water . Given the
depth of water, Where fish is located. Being
h and the critical angle for water-air
interface being i c find out by drawing a
suitable ray diagram the relationship between
the radius of the cone and the height h
.
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19. Two identical coils, each of radius R and
number of turns N are lying in
perpendicular planes such that their
centres coincide. Find the magnitude and
direction of the resultant magnetic field
at the centre of the coils, if they are
carrying currents I and I
respectively. 20. Explain briefly, giving a
suitable diagram, how an unpolarised light
incident on the interface separating two
transparent media gets polarised on
reflection. Deduce the necessary condition
for it.
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21. Draw a ray diagram to show the formation of
the image of an object placed on the axis
of a convex refracting surface, of radius
of curvature R, separating the two media
of refractive indices n1 and n2 (n2 gt
n1) . Use this diagram to deduce the
relation - , where u
and v represent respectively the distance of
the object and the image formed.
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22. (a) How does an oscillating charge produce
electromagnetic wave? Explain. (b)
Draw a sketch showing the propagation of a
plane e.m. wave along the Z direction, clearly
depicting the directions of oscillating
electric and magnetic field vectors.
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23. Answer the following (i) Do the frequency
and wavelength change when light passes from
a rarer to a denser medium? (ii) Why is the
value of the angle of deviation for a ray
of light undergoing refraction through a
glass prism different for different colours of
light? (iii) In a single slit diffraction
experiment, the width of the slit is
reduced to half its original width. How
would this affect the size and intensity of
the central maximum?
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24. State Gausss law. A thin straight
infinitely long conducting wire of linear charge
density ? is enclosed by a cylindrical surface
of radius r and length l its axis
coinciding with the length of the wire. Obtain
the expression for the electric field, indicating
its direction, at a point on the surface of the
cylinder. or An electric dipole is kept
in a uniform electric field. Derive an
expression for the net torque acting on it and
write its direction. State the conditions under
which the dipole is in (i) stable and (ii)
unstable equilibrium
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25. Draw the transfer characteristic of a base
biased transistor in CE configuration.
Mark the regions where the transistor can
be used as a switch. Explain briefly its
working. 26. Write Einsteins photoelectric
equation, giving the main points of the
photon picture of electromagnetic
radiation on which this equation is
based. State three observed features of
photoelectric effect which can be
photoelectric effect which can be explained by
Einsteins equation.
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27. The figure shows the V I characteristics of
a semiconductor device. Identify this
device. Explain briefly, using the
necessary circuit diagram, how this
device is used as a voltage regulator
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28. (a) Derive the relation between current
density and potential difference
V across a current carrying conductor
of length l area of cross- section A
and the number density n of free
electrons. (b) Estimate the average drift
speed of conduction electrons in a copper
wire of cross- sectional area1.0 X 10-7 m2
carrying a current of 1.5 A. Assume that
the number density of conduction
electrons is 9 x 1028 m-3 (or)
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Use Kirchhoffs rules to obtain the balance
condition in a Wheatstone bridge. Calculate the
value of R in the balance condition of the
Wheatstone bridge, if the carbon resistor
connected across the arm CD has the colour
sequence red, red and orange, as is shown in the
figure. If now the resistances of the arm BC and
CD are interchanged, to obtain the balance
condition, another carbon resistor is connected
in place of R. What would now be the sequence of
colour bands of the carbon resistor?
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29. (a) Using Bohrs theory of hydrogen atom,
derive the expression for the total energy
of the electron in the stationery states
of the atom. (b) If electron in the atom
is replaced by a particle (muon) having
the same charge but mass about 200 times
as that of the electron to form a muonic
atom, how would (i) the radius and (ii)
the ground state energy of this affected?
(c) Calculate the wavelength of the first
spectral line in the corresponding Lyman
series of this atom. (or)
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• Define the term activity of a given sample of
  radionuclide. Write the expression for the law of
  radioactive decay in terms of the activity of a
  given sample.
• A radioactive isotope has a half life of T
  years. How long will it take the activity to
  reduce to 3.125 of its original value?
• When a nucleus (X) undergoes ß-decay, the
  transforms to the nucleus (Y), does the pair (X,
  Y) form isotopes, isobars or isotones? Justify
  your answer.

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30. (a) A voltage V V2 sin ?t applied to a
series LCR circuit drives a current i
i2 sin ?t in the circuit. Deduce the
expression for the average power
dissipated in the circuit. (b) For
circuits used for transporting electric
power, a low power factor implies large power
loss in transmission. Explain (c)
Define the term wattles current.
(or)
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(a) Starting from the expression for the Lorentz
magnetic force acting on the free charge
carriers of a conductor moving in a
perpendicular magnetic field, obtain the
expression for the motional emf
induced. (b) Hence deduce the expression for the
power delivered by the source and the power
dissipated as Joule heat. (c) A straight
wire extending from east to west falls with
a speed v at right angles to the horizontal
components of the Earths magnetic field. Which
end of the wire would be at the higher
electrical potential and why?