Tilka Manjhi Bhagalpur University 2007 B.Sc Physics PHY SUB - Question Paper

COPYRIGHT RESERVED AA(H-1)PHY


2007

Time: three hours

Full marks: 50


PHYSICS SUB/GEN
ans 5 ques..Selecting at lowest 1 from Group B and C Group-A is compulsory

GROUP-A
1. Indicate the accurate ans in the following:
(a) Which of the subsequent is not a magnetic property?
(1)permeability (2) Susceptibility (3) Hysteresis(4)resistivity

b) if p is the polarization of a dielectric slap, then
1)p=1 2)p=2 3)p=3 4)p=4


c ) the unit of peltier coefficient is
(1)joule per coulomp per Kelvin (2) joule per Kelvin
(3) joule per coulomp (4) joule per coulomb2

(d)the time constant of a circuit is the time in which current decays by
(1) 25 % (2) 37% (3) 50% (4) 63%
(e)the alternating current through an inductance

(1) lags behind the voltage in phase by an angle pie
(2) leads the voltage in phase by and angle pie
(3) lags behind the voltage in phase by an angle by and angle 90.
(4)Leads the voltage in phase by an angle 90.

(f) curie is the unit of radioactivity which is equal to
(1) 1 disintegration per 2nd (2) 3.7 * 10 ^10 disintergration per
Second
(3)10 ^6 disintegration per 2nd (4) 10 ^4 disintergration per second

(g) Electron volt is the unit of
(1) charge (2) potential defference (3) current (4) energy

(h) in younger sit experiment,if distance ranging from slits is halvaed and
distance ranging from slits screen is doubled ,the fringe width becomes
(1) half (2) double (3) 4 times (4) 8 times

(i) Maxwell,s electromamagnetic theory of light suggests that the lighit
consists of oscillations of
(1)magnetic vector alone (2)electric vector alone
(3) electric and magnetic vectors parallel to every other

GROUP-B
two discuss the phenomena of electric polarization of a dielectric substance
What do you mean by electric intensity,electric polarization and electric
Displacement for a medium ? obtain the relation ranging from them

three (a) What is curie point ? Magnetic behaviour of magnetic substances reduces
With increasing temperature.comment
(b) Why ferromagnetism is obtained in solids only and not in fluids?

4 Give the construction of moving coil ballistic bavanometer and deduce the
Formula the quality of electricity flowing through it. State the condition under which it is (a) ballistic and (b) dead beat

5 give an account of the theory of radioactive disintegration. discuss the term half-life time of a radioactive atom. Deduce an expression for the half-time of a radioactive substance in terms of it’s a radioactive constant.

GROUP-C
6 What do you by diffraction of light? explain diffraction at a single slit.
How is the width of center maximum changed when-
(a)slit width is reduced (b) the distance ranging from slit and screen
increased?

7 State Maxwell’s formula for uniform plane electromagnetic waves in free space (vacuum)

8 How does Bohr’s theory of hydrogen atom discuss the various series of spectral lines of hydrogen?
Draw energy level diagram.Give the limitation of Bohr’s atomic model.

9 What od you understand by polarization of light? How would you produce and detect plane, circularly and elliptically polarized lights?

Earning:   Approval pending.