Download Q.1 Name the mode of propagation of radio waves which travel in

Q.1
Name the mode of propagation of radio waves
which travel in straight line from transmitting
antenna to the receiving antenna?
Q.2
What is the meaning of term attenuation in the
communication system?
Q.13
Draw symbol and reverse bias V-I characteristics
of zener diode. Explain briefly, which property of
the characteristics enables us to use zener diode
as voltage regulator.
Q.14
The energy of electron in the hydrogen orbit is
given by -13.6/n2 in eV. Use this expression to
show that the hydrogen atom can’t have energy
of -6.8eV. [b] Spacing between the lines within
given set f observed hydrogen spectrum
decreases as ‘n’ increases.
Q.3
A parallel beam of monochromatic light falls
normally on a single narrow slit. How does
angular width of the central maximum in the
resulting diffraction pattern depend on the
wavelength of the light used?
Q.4
Assuming the nuclei to be spherical in shape, how
does the surface area of nucleus of mass number
A1, compare with that of nucleus of mass number
A2?
Q.15
Find out the expression for the magnetic field at a
point on the central axis of the solenoid carrying
current I and having number of turns per unit
length n’.
Q.5
Out of the two characteristics the mass number
and the atomic number of a nucleus, which does
not change during beta decay?
Q.16
Modern telescopes prefer using suitable mirrors
over using suitable lenses. Give two reasons for
this preference.
Q.6
A physical quantity associated with electrical
conductivity has unit ohm-meter. Identify this
physical quantity.
Q.17
Q.7
The frequency of oscillation of the electric field
vector of certain em wave has frequency 5 x
1014Hz. What is the frequency of oscillation of
corresponding magnetic field vector and to which
part of em spectrum does it belong?
Why is it necessary to slow down the neutrons,
produced through the fission of U235 nuclei, to
sustain the chain reaction? What type of nuclei
are needed for slowing down of the neutrons?
Q.18
An ac voltage is applied across an LCR circuit.
Draw the phasor diagram for this circuit when [a]
capacitive reactance exceeds the inductive
reactance [b] when inductive reactance exceeds
the capacitive reactance. Use E=E0 sing ωt
Q.19
Define coefficient of mutual induction and write
its SI unit. Obtain the mutual inductance of a pair
of circular coils of radius r1 and r2 and r1<<r2. The
coils have been placed coaxially with their
centers coinciding.
Q.20
The amplitude modulated carrier wave of angular
frequency ωc, contains frequency ωc, ωc+ωm, ωcωm where ωm is the frequency of modulating
signal. Discuss in brief with the help of block
diagram, the essential details of simple method
used for detecting the modulating signal for this
modulated carrier wave.
Q.21
Name and define the two elements of the earth’s
magnetic field other than the horizontal
component of earth’s magnetic field. Why do we
say that at places like delhi and Mumbai, a
magnetic needle shows true north direction
accurately as compared to other places in india.
Q.22
A long straight wire of cross section, of radius ‘a’
carries steady current I. The current is uniformly
distributed across the cross section of the wire.
Use Ampere’s circuital law to show that the
Q.8
Q.9
Q.10
A [a] series [b] parallel combination of two given
resistors is connected, one by one, across a cell.
In which case will the terminal potential
difference across the cell have higher value?
Write Einstein’s photoelectric equation in terms
of the stopping potential and the threshold
frequency for a given photosensitive material.
Draw a plot showing variation of stopping
potential vs frequency of the incident radiation.
An em wave is travelling in a medium with
velocity v=v i. The electric field oscillations, of this
em wave are along y axis [a] identify the direction
in which oscillations of magnetic field vector
takes place. [b] How are the magnitudes of
electric and magnetic field in em wave related to
each other.
Q.11
For what KE of proton, will its associated deBroglie wavelength by 16.5nm?
Q.12
Define the dipole moment of electric dipole. How
does electric potential due to dipole vary on the
dipole axis as function of r, distance of field point
from the center of the dipole at large distances?
magnetic field, due to this wire, in the region
inside the wire, increases in direct proportion to
the distance of the field from point on the axis of
the wire. Write the value of this magnetic field on
the surface of the wire.
Q.23
Q.24
In YDS experiment, the two slits are kept 2mm
apart and the screen is positioned 140cm away
from the plane of the slits. The slits are
illuminated with light of wavelength600nm. Find
the distance of the third bright fringe, from the
central maximum, in the interference pattern
obtained on the screen. If the wavelength of
incident light were changed to 480nm, find out
the shift in the position of third bright fringe from
the central maximum.
The two plates of a parallel capacitor are 5mm
apart. A slab of dielectric, of thickness 4mm is
introduced between the plates with its faces
parallel to them. The distance between the plates
is adjusted so that the capacitance of the
capacitor becomes equal to its original value. If
the new distance between the plates is equal to
8mm, what is the dielectric constant of the
dielectric used?
Q.25
A series LCR circuit R=200Ω, L= 4/π H, C=50/π μF.
This series combination is connected across an ac
source of 220V, 50Hz. Calculate the [a] the
impedance of the circuit [b the peak value of the
current flowing in the circuit. Calculate the power
factor of this circuit and compare this value with
one at its resonant frequency.
Q.26
[a] Two point charges q1, q2 initially at infinity, are
brought one by one to points P1 and P2, specified
by position vectors r1 and r2 relative to some
origin. What is the potential energy of this
configuration?
[b] Define an equipotential surface, Draw
schematically
the
equipotential
surfaces
corresponding to field that uniformly increases in
magnitude but remains constant in direction.
Q.27
Q.28
What are coherent sources of light? In YDS
experiment, two slits are separated by 3mm
distance and illuminated by light of wavelength
480nm. The screen is at distance of 2m from the
plane of the slit. Calculate the separation
between the 8th fringe and 3rd dark fringe
observed with respect to the central fringe.
The same input signal is applied to both the
[input] terminals of given logic gate. If the output
is the [a] same as the common input signal[b]
inverted with respect to the [common] input
signal, identify the logic gate involved in each
case.
[2] Write the truth tables for each tables for each
of the combination shown below. Also identify
the logic operations performed by them
Q.29
State the two rules that serve as general rules for
analysis of electrical circuit. Use these rules to
write the three equations that may be used to
obtain the values of the three unknown currents
in the branches of the circuit given below
[a] State the working principle of a potentiometer
with the help of circuit diagram
[b] Two cells of emf E1 and E2 and internal
resistance r1 and r2 are connected in parallel with
each other. Obtain expressions for the equivalent
emf and equivalent internal resistance of this
parallel combination.
Q.30
Draw the ray diagram showing the passage of
light through a glass prism. Hence obtain a
relation between the angles of deviation,
incidence and emergence and angle of prism.
[b] Show that no ray can pass through the prism
whose refracting angle A is greater than twice the
critical angle for the material of the prism.