2ND
YEAR PHYSICS GUESS FOR EXAMINATION 2023
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SHORT QUESTIOhNS
(i) The potential is constant throughout a given region of space. Is the
electrical field zero or non-zero in this region? Explain.
(ii) How can you identify that which plate of a capacitor is positively
charged?
(iii) Describe the force on a positive point charge when placed between
parallel plates;
a. With similar and equal charges b. with opposite and equal charges
(iv) Electric lines of force never cross. Why?
(v) If a point charge q of mass m is released in a non-uniform electric
field with field lines pointing in the same direction, will it make a
rectilinear motion?
(vi) Do electrons tend to go to region of high potential or of low potential?
(vii)
A potential difference is applied
across the ends of a copper wire. What is the effect on the drift velocity of
free electrons by;
a. Increasing the potential difference b.
decreasing the length and the temperature of the wire
(viii)
Do bends in a wire affect its
electrical resistance? Explain.
(ix) Why does the resistance of a conductor rise with temperature?
(x) What are the difficulties in testing whether the filament of a lighted
bulb obeys Ohmโs law?
(xi) Is the filament resistance lower or higher in a 500 W, 220V light bulb
than in a 100W, 220 V bulb?
(xii)
Describe a circuit which will give a
continuously varying potential.
(xiii)
A plane conducting loop is located in
a uniform magnetic field that is directed along the x-axis. For what
orientation of the loop is the flux a maximum? For what orientation is the flux
a minimum?
(xiv)
A current in a conductor produces a
magnetic field, which can be calculated using Ampereโs law. Since current is
defined as the rate of flow of charge, what can you conclude about the magnetic
field due to stationary charges? What about moving charges?
(xv)
Describe the change in the magnetic
field inside a solenoid carrying a steady current I,
if (a) the length of the solenoid is doubled but the number of turns
remains the same and (b) the number of turns is doubled, but the length remains
the same.
(xvi)
At a given instant, a proton moves in
the positive x direction in a region where there is magnetic field in the
negative z direction. What is the direction of the magnetic force? Will the
proton continue to move in the positive x direction? Explain.
(xvii)
How can a current loop be used to
determine the presence of a magnetic field in a given region of space?
(xviii) Why the resistance of an ammeter should be very low?
(xix)
Does the induced emf in a circuit
depend on the resistance of the circuit? Does the induced current depend on the
resistance of the circuit?
(xx)
A light metallic ring is released from
above into a vertical bar magnet. Viewed for above, does the current flow
clockwise or anticlockwise in the ring.
(xxi)
Does the induced emf always act to
decrease the magnetic flux through a circuit?
(xxii)
How would you position a flat loop of
wire in a changing magnetic field so
that there is no emf induced in the loop?
(xxiii) In a certain region the earthโs magnetic field point vertically down.
When a plane files due north, which wingtip is positively charged?
(xxiv) Show that 
have the same units.
(xxv)
Is it possible to change both the area
of the loop and the magnetic field
passing through the loop and still not have an induced emf in the loop?
(xxvi) Can an electric motor be used to drive an electric generator with the
output form the generator being used to operate the motor?
(xxvii) A suspended magnet is oscillating freely in a horizontal plane. The
oscillations are strongly damped when a
metal plate is placed under the magnet. Explain why this occurs?
(xxviii) When the primary of a transformer is connected to A.C mains the current
in it; (a) is very small if the
secondary circuit is open, but (b)
increases when the secondary circuit is closed. Explain these facts.
(xxix) Name the device that will (a)
permit flow of direct current but oppose the flow of alternating current (b) permit flow of alternating current
but not the direct current.
(xxx)
How many times per second will an
incandescent lamp reach maximum brilliance when connected to a 50Hz source?
(xxxi) A circuit contains an iron-cored inductor, a switch and a D.C. source
arranged in series. The switch is closed and after an interval reopened.
Explain why a spark jumps across the switch contacts?
(xxxii) How does doubling the frequency affect the reactance of (a) an inductor (b) a capacitor?
(xxxiii) In a R-L circuit, will the current lag or lead the voltage? Illustrate
you answer by a vector diagram.
(i)
Differentiate b/w Bulk and shear
modulus.
(ii) What do you mean by ultimate tensile stress?
(iii) How p-type and N-type substances are made from intrinsic
semi-conductors.
(iv) Differentiate b/w paramagnetic and ferromagnetic materials.
(v) What do you mean by coercivity and coercive current.
(vi) How does the motion of an
electron in a n-type substance differ from the motion of holes in a p-type
substance?
(vii)
Whatis the net charge on a n-type or a
p-type substance?
(viii)
The anode of a diode is 0.2V positive
with respect to its cathode. Is it forward biased?
(ix) Whatis the effect of forward and reverse biasing of a diode on the width
of depletion region?
(x) Why ordinary silicon diodes do not emit light?
(xi) Why a photo diode is operated in reverse biased state?
(xii)
The potential is constant throughout a
given region of space. Is the electrical field zero or non-zero in this region?
Explain.
(xiii)
How can you identify that which plate
of a capacitor is positively charged?
(xiv)
Describe the force on a positive point
charge when placed between parallel plates;
a. With similar and equal charges b. with opposite and equal
charges
(xv)
Electric lines of force never cross.
Why?
(xvi)
If a point charge q of mass m is
released in a non-uniform electric field with field lines pointing in the same
direction, will it make a rectilinear motion?
(xvii)
Do electrons tend to go to region of
high potential or of low potential?
(xviii) A potential difference is applied across the ends of a copper wire. What
is the effect on the drift velocity of free electrons by;
a. Increasing the potential difference b.
decreasing the length and the temperature of the wire
(xix)
Do bends in a wire affect its
electrical resistance? Explain.
(xx)
Why does the resistance of a conductor
rise with temperature?
(xxi)
What are the difficulties in testing
whether the filament of a lighted bulb obeys Ohmโs law?
(xxii)
Is the filament resistance lower or
higher in a 500 W, 220V light bulb than in a 100W, 220 V bulb?
Describe a circuit which will give a
continuously varying potential.
(i)
Bohrโs theory of hydrogen atom is
based upon several assumptions. Do any of these assumptions contradict classical
physics?
(ii)
Can the electron in the ground state
of hydrogen absorb a photon of energy 13.6eV?
(iii)
Is energy conserved when an atom emits
a photon of light?
(iv) What do we mean when we say that the atom is excited?
(v)
What are isotopes? What do they have
in common and what are their differences?
(vi) Why must a Geiger Muller tube for detecting ฮฑ-particles have a very thin
end window? Why does a Geiger Muller tube for detecting 
-rays not need a
window at all?
(vii) What do we mean by the term critical mass?
(viii)
What factors make a fusion reaction
difficult to achieve?
(ix) How can radioactivity help in the treatment of cancer?
2nd Year Physics Past Papers
LONG QUESTION
Q. (a) Define and
explain polarization of dielectric, give a complete description of
dielectric constant after establishing
the relation for capacitance of a parallel plate capacitor. (05)
(b) in Bohrโs atomic model of hydrogen atom, the electron is
in an orbit around the nuclear proton at distance of
with a speed of 
(e = 
mass of electron = 
). Find
(i) The electric potential that a proton
exerts at this distance (ii) total energy of the atom in eV (iii) The ionization
energy for the atom in
eV. (03)
. Q (a) State kickoffโs voltage rule and use it
to derive the expression for wheatstone bridge. (05)
(b) Find the current
which flows in all the resistance of the circuit of following Fig. (03)
Q. (a) Describe Lorentz force law and give
procedure and derive relations for conversion of galvanometer into a
Voltmeter and ammeter.
(05)
(b) What current should
pass through a solenoid that is 0.5 m long with 10.000 turns of copper wire so
that it will
have a magnetic field of
0.4T? (03)
Q. (a)
Briefly describe motional emfโs equation with emphasis on the โ ive sign and
use it to derive the equation of a
transformer along with itโs
principle and construction. (05)
(b) a copper ring has a
radius of 4.0cm and resistance of 1.0 m โฆ. A magnetic field is applied over the
ring,
perpendicular to its plane.
If the magnetic field increases from 0.2T to 0.4T in a time interval of 5 x10โ3s, what is the
current in the ring during
this interval?
(03)
Q. (a)
describe in detail the behavior of a capacitor with the passage of AC through
it. (05)
(b) A 10mH, 20 โฆ coil is
connected across 240V and 180/ฯ Hz source. How much power does it dissipate? (03)
(a)Write a detailed note
on transistor as an amplifier. (05)
(b)The Length of a steel wire is 1.0 m and its cross-sectional
area is 
. Calculate the work
done in
stretching the wire when a force of 100N is applied within
the elastic region. Youngโs modulus of steel is
. (03)
Q. (a)Write detailed note on photoelectric effect
alongwith Einsteinโs explanation. (05)
(b)A 90 keV X-rays photon
is fired at a carbon target and Compton scattering occurs. Find the wavelength
of the
incident photon and the
wavelength of the scattered photon for scattering angel of (a) 30
(b) 60. (03)
Q. (a)Find the
expressions for (i) Radius & (ii) energy of a hydrogen atom. (05)
(b)Calculate the longest
wavelength of radiation for the Paschen series. (03)
Q. (a)Define and
explain polarization of dielectric, give a complete description of
dielectric constant after establishing
the relation forcapacitance of a parallel plate capacitor. (05)
(b)in Bohrโs atomic model of hydrogen atom, the electron is
in an orbit around the nuclear proton at distance of
2nd Year Physics Past Papers
2nd Year Physics Past Papers
Labels: 12th class guess, 2nd year, 2nd Year Guess
