Q. "Om Sai Ram"
1:Name the
experiment for which the following graph, showing the variation of intensity of
scattered electrons with the angle of scattering, was obtained.
Q.2: What are the dimensions of magnetic flux? What is the
flux associated with a plane coil of
area A , having N turns in
a uniform magnetic field B ?
Q.3: One billion electrons pass
from A to B in a conductor in 1 milli second. What is the direction and magnitude of current?
Q.4: A rectangular current loop is
in an arbitrary orientation in an external uniform magnetic field. Is any work required to rotate the loop about an
axis perpendicular to its plane? Explain.
Q.5
Define electrical susceptibility. How it is related to dielectric constant.
Q.6
A plane EM wave of frequency 25 Hz travels in free space along X direction. At
a Particular point in space and time the electric vector is E = 6.3j V/m.
Calculate B at this point.
Q.7 What is the effect on the following on inserting a
dielectric in a parallel plate capacitor:
(a) Capacitance (b) Charge on the plates of the capacitor
Q.8State
laws which are used for calculating equivalent resistance of unbalanced wheat
stone bridge.
OR
Calculate the equivalent resistance of the
following circuit.
Q.9: Draw a well labelled diagram to show Earth’s magnetic field and angles associated with it.
Q.10: Calculate the current flowing in the
following circuit and the heat loss across 2.2 kΩ resistor in 10 seconds. 
Q11.An
inductor L of reactance XL is connected in series with a bulb B to
an A.C. source as shown in the figure. Briefly explain how the brightness of
the bulb changes when
(a)
Number
of turns of the inductor is reduced and
(b)
A
capacitor of reactance XC =XL is included in series in
the same circuit.
Q.12:Draw
hysteresis loops for soft iron and steel. Hence, explain why soft iron is used
for preparing electromagnets while steel is used for preparing permanent
magnets.
Q.13: (a) The coefficient of mutual
induction of the two coils is 0.5 H. If the current is increased from 2 to 3 A
in 0.1 seconds in one of them, then find the induced EMF in the second coil.
(b) Give two advantages of eddy currents in electrical appliances.
Q. 14: The dielectric strength of air is 3 x 106 V/m.
What is the maximum charge that can be safely stored on a sphere of radius 10m?
Q.15:An electron is moving at 106
m/s in a direction parallel to a current of 5 A flowing through an infinitely
long wire at a perpendicular distance of 10 cm in air. Calculate the magnitude
of force experienced by an electron.
Q. 16. An alpha particle and a proton accelerated by the same
potential difference enter into a magnetic field. Find the ratio of their
radius and the ratio of their frequency.
Q.17:
(a) Does every charge give out electromagnetic waves? Explain very briefly.
(b) The magnetic field in a plane EM
wave is given by
By = 2 × 10
-7 sin (0.5 × 103 z + 1.5 × 1011 t) T.
(i)
What is the frequency of the wave?
(ii)
Write an expression for the
electric field.
Q.18: Use Kirchhoff’s
laws to find the currents I1,
I2 and Ig in Wheatstone bridge shown in figure.
Q.19: A conductor of length l is connected to a dc
source of emf V. if the length of the conductor is tripled by stretching it,
keeping V constant, explain how do the following factors vary in the conductor:
(1) Drift speed of electron (2 ) Resistivity
Q.20: (a) Distinguish between
resistance, reactance and impedance for an AC circuit.
(b) What do we mean by the term phasors? Draw
a phasor diagram for an AC circuit with a capacitor.
Q21.X -ray of wavelength λ falls on photosensitive
surface emitting electron. Assuming that the work function of the surface can
be neglected, prove that de-Broglie wavelength of electron emitted will be [ h
λ/2mc]1/2.
Q.22: Two parallel
conductors are carrying current I1 and I2 are kept ‘r’
distance apart. Deduce an expression for force unit length acting between them.
Define one ampere using this relation.
Q.23: Draw a circuit diagram for a potentiometer
circuit used to find internal resistance of a cell and deduce the expression
for internal resistance in terms of the balancing lengths.
Q.24:Sketch
the graphs, showing the variation of stopping potential with frequency of
incident radiations for two photosensitive materials A and B having threshold
frequencies ƒ1 > ƒ2 respectively. (1) Which of the two
metals A Or B has higher work function? (2) Will the slope of both curves be
same? Justify your answer.
Q.25:
State Lenz’s law. Two identical metallic rods one of copper and another of
aluminum are rotated with same angular speed w in presence of same magnetic
field. In which case (1) the induced emf (2) the induced current, will be more
and why?
Q.26: State the principle of working of
galvanometer. In galvanometer (i) concave shaped poles are used (ii)
phosphor-bronze alloy is used for the suspension wire. Explain why? The current
sensitivity of moving coil galvanometer is 5 divisions/mA and voltage
sensitivity is 20 division/volt. Calculate the resistance of galvanometer.
Q.27:
In L-R series circuit, the potential difference across the inductor ‘L’ and the
resistor ‘R’ are 120 V and 90 V respectively and rms value of current is 3 A
(1) calculate r.m.s voltage across the circuit. (2) Is the algebraic sum of the
voltage across two components more than the applied voltage? If yes, explain
the reason (3) Calculate the phase angle between the voltage and current.
OR
A resistor of resistance 400Ω, and a capacitor of
reactance 200Ω,are connected in series to a 220V,50Hz a.c. source .If the
current in the circuit is 0.49 ampere find the (i) voltage across the resistor
and capacitor(ii) value of inductance required so that voltage and current are
in same phase.
Q.28: Explain the effect of introducing a dielectric
slab between the plates of a parallel plate capacitor on its
capacitance. Derive an expression for its capacitance with the dielectric slab,
what is the effective capacitance across XY of the capacitor of capacitance if
the capacitor with air/vacuum between the plates of area A each and distance d
apart was Co.
OR
State gauss theorem in electrostatics. Derive an expression for the
electric field strength near an infinite plane sheet of charge. A point charge
of +10μC is at a distance 5cm directly above the centre of a square of side
10cm as shown in the figure. What is the magnitude of electric flux through the
square?
Q.29:
With the help of a labeled diagram explain the construction and working of an
a.c. generator. Deduce the expression for emf induced. What is average and root
mean square value of emf induced ?
Q.30: (a) Give two advantages of
the presence of a soft iron core in a moving coil galvanometer.
(b) How can you turn a galvanometer
into a voltmeter? Give the necessary equation.
(c) A galvanometer having a coil
resistance 100 Ω gives a full scale deflection when a current of 1 mA is passed
through it. What is the value of the resistance which can convert this galvanometer into a meter giving full scale
deflection for a potential difference of 10 V?
Physics Classes By Er.Shyam Pachori add: C.L 81 D.D Nagar Mob.: 9039803981 Batches MWF Time: 3:30 - 5 Pm
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