Q. Define common emitter output characteristic for a transistor. Draw a circuit diagram for studying the characteristics of n-p-n transistor in common emitter configuration.
Among emitter, base and collector regions of a transistor which one is:
(a) largest in size and (b) most heavily doped?

Q. Draw propagation diagram of a linearly polarised electromagnetic wave and write any two properties of electromagnetic waves.
The amplitude of the magnetic field associated with an electromagnetic wave in vacuum is $B_0=50\times {10}^{-8}$ tesla. Write the value of amplitude of the electric field in $V/m$ associated with the wave.

Q. A ray of light is incident at the Brewster's angle on the surface of a transparent medium. Deduce Brewster's law by using Snell's law.

Q. Write the relation between object distance ($u$), image distance ($v$) and focal length ($f$) for a concave mirror.

Q. Write the statement of Gauss's law.

Q. On the basis of Bohr's postulates derive an expression for orbital velocity of an electron in $n$th stationary orbit of hydrogen atom.
The ground state energy of hydrogen atom is $(-X)eV$. What will be the kinetic energy of the electron in this state?

Q. Define half-life of a radioactive substance and write the relation of half-life with the following:
(a) Radioactive decay constant (disintegration constant)
(b) Mean life of a radioactive substance.

Q. Match the following:

Column I	Column II
(a) Resonant frequency	(i) $VI\cos \varphi$
(b) Quality factor	(ii) $\frac{1}{2}L{I}^2$
(c) Average power	(iii) $\frac{1}{\sqrt{LC}}$
(d) Impedance	(iv) $\sqrt{R^2+{(X_L-X_C)}^2}$
(e) Magnetic potential energy	(v) $\frac{-E}{\left(\frac{dI}{dt}\right)}$
(f) Coefficient of self-induction	(vi) $\frac{w_{0}L}{R}$

1. $a\to iii,b\to v,c\to i,d\to iv,e\to vi,f\to ii$
2. $a\to ii,b\to iv,c\to v,d\to iii,e\to vi,f\to i$
3. $a\to ii,b\to iii,c\to i,d\to iv,e\to v,f\to vi$
4. none of these

Q. Write the relation in radius $R$ and mass number $A$ of a nucleus.

Q. Define angle of inclination (magnetic declination).
In the magnetic meridian of a certain place, the horizontal component of earth's magnetic field is $0.25$ gauss and the dip angle is ${60}^o$. At this place find the value of earth's magnetic field.

Q. A message signal of peak voltage $20V$ is used to modulate a carrier wave of peak voltage $30V$. Determine the modulation index.

Q.

(i) Define rectification.
(ii) Draw a circuit diagram of a full-wave rectifier.
(iii) Semi-conductor related to given energy band diagram is:
n-type semi-conductor, p-type semi-conductor or intrinsic semi-conductor.

Q. (a) Write the name of the lens used to correct nearsightedness (myopia)
(b) What will be the radius of curvature of a concave mirror of focal length $10cm$?

Q. Define the following:
(a) Total internal reflection
(b) Diffraction of light
(c) Refraction of light

Q. How the effective power radiated by an antenna will be changed if the wavelength of radiation is decreased?

Q. Calculate the potential at a point due to a charge of $3\times {10}^{-9}C$ located $9\times {10}^{-2}m$ away from it.

Q. Define mass defect of a nucleus. Binding energy of ${{}_{8}O}^{16}$ is $127.5MeV$. Write the value of its 'binding energy per nucleon'. Write the value of $1eV$ energy in joule.

Q. In the figure, resistivities of two conductors of same material are ${\rho }_1\Omega -m$ and ${\rho }_2\Omega -m$ respectively. Write the value of ratio of ${\rho }_1$ and ${\rho }_2$

Q. Select one donor impurity among the following:
Boron$\left(B\right)$, Aluminium $\left(Al\right)$, and Arsenic $\left(As\right)$.

Q. Write de Broglie hypothesis. Obtain the formula for de Broglie wavelength of an electron which is accelerated from rest through a potential $V$ volt.

Q. (a) Derive a relation for electric field due to an electric dipole at a point on the equatorial plane of the electric dipole. Draw necessary diagram.
(b) An electric dipole of charge $\pm 1$ $\mu C$ exists inside a spherical Gaussian surface of radius $1cm$. Write the value of outgoing flux from the Gaussian surface.
(c) Potential on the surface of a charged spherical shell of radius $10cm$ is $10V$. Write the value of potential at $5cm$ from its centre.

Q. Write the name of electromagnetic wave produced by vacuum tube magnetron.

Q. Explain briefly the following terms used in communication system:
(a) modulation; and (b) transducer.

Q. Write average value of current over a complete cycle of alternating current.

Q. Write the statement of Lenz's law of electromagnetic induction.
A $2m$ horizontal long straight conducting wire extending from east to west direction is falling with a speed of $5m/s$ perpendicular to the horizontal component of the earth's magnetic field $0.3\times {10}^{-4}$ tesla. Calculate the value of instantaneous emf induced across the ends of wire.

Q. (a) NAND gates are also called universal gate. Why?
(b) Draw a logic symbol of OR gate.
(c) Write the value of output $y$ in the given circuit:
(d) Write the name of the diode used in voltage regulation.

Q. (a) Define potential gradient.
(b) Write Kirchhoff's junction rule.
In the given diagram write the value of current $I$.

Q. The work function of a metal is $3.31\times 1.6\times {10}^{-19}$ joule. Calculate its threshold frequency in hertz.

Q. Define stopping potential (cut-off potential) with reference to photoelectric effect.

Q. Write the method to determine the value of an unknown resistance by meter bridge and derive necessary formula. Draw a circuit diagram.