4254ajay Sharma Paper

8/13/2019 4254ajay Sharma Paper

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12. lane electromagnetic wa)e of frequency 2* 650 tra)els in free sace along the X -

direction. t a articular oint in sace and time its electric field )ector 7 is .! j %8m.'alculate the magnetic field )ector B at this oint. Write its e9ressions for 7 and B.

1!. Why we need a carrier wa)e of )ery high frequency in the modulation of signals?

carrier wa)e of ea )oltage 2# % is used to transmit a message signal. What should be

the ea )oltage of modulating signal for achie)ing modulation inde9?

1(. X and Y are two arallel late caacitors ha)ing same area of lates and same searation

between the lates as shown in the figure. X has air between the lates and Y has a

dielectric of dielectric constant k=4.

:i; 'alculate the otential difference between the lates of X and Y .

:ii; What is the ratio of electrostatic energy stored in X and Y ?

1*. <ind the equi)alent resistance between terminals X and Y of networ shown in figure.

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1. Write nuclear equations for

(a) - -decay of = :b; >-decay of '

17. con)e9 lens :of refracti)e inde9 n g ; has focal length f in air. Write an e9ression for its

focal length when immersed in a liquid of refracti)e inde9 nl . se the e9ression to find

the focal length of glass lens :nl @1.*; when immersed in water :nw@ ;. :"he focal length

of lens in air is 2* cm.;

1. se Airchhoff’s laws to find the currents 1, 2 and g in Wheatstone bridge shown in

figure.

13. Draw hysteresis loos for soft iron and steel. 5ence, e9lain why soft iron is used for

rearing electromagnets while steel is used for rearing ermanent magnets.

2#. Dri)e a relation between decay constant and a)erage life.

21. Draw circuit diagram of a common emitter transistor amlifier using npn transistor. Why

the )oltage gain of his amlifier is more than that of common base transistor amlifier?

22. <ind the e9ression of amlitude modulated wa)e.

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2!. 79lain how will you combine cells to obtain ma9imum current if

:i; nternal resistance of cells are low.

:ii; nternal resistance of cells are high.

2(. What do you mean by an ideal &unction diode? Draw characteristic cur)e of forward and

re)erse biasing of a ractical p-n &unction diode. 79lain the terms threshold )oltage and

re)erse saturation current.

OR

What is a hotodiode? 79lain its woring. hotodiode is fabricated from a

semiconductor with a band ga of 2. e%. 'an it detect a wa)elength of ### nm?

25. white light ray incident on face AB of rism is shown in fig. 'omlete the ath of three

raysC red, yellow and blue. t what angle should a ray of light be incident on one face of

a rism of refracting angle # so that it &ust suffers total internal reflection at the other

face ? "he refracti)e inde9 of material of the rism is 1.*2(.

2. <ind an e9ression for the force and torque acting on a rectangular current carrying coil

in a uniform magnetic field. se it to find the linear relation between deflection and

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current of a mo)ing coil gal)anometer. 5ence, e9lain why and how the magnetic field in

gal)anometer is made radial.

2$. Draw energy le)el diagram of atomic hydrogen. 4ame and show all he fi)e series found

in emission sectrum of hydrogen on his diagram. lso name the regions of sectrum to

which these series lie.

2. Write <araday’s laws of electromagnetic induction. 5ow will you find the direction of

induced emf ? find an e9ression for induced emf in a rod of length l mo)ing with

)elocity % erendicular to a magnetic field of induction B.

OR

With the hel of a labeled diagram e9lain the construction and woring of an a.c.

generator. Deduce the e9ression for emf induced. What is a)erage and root mean square

)alue of emf induced ?

23. What do you mean by coherent sources of light ? 'an two 1## W bulbs laced at a small

searation be coherent ? 79lain.

<ind an e9ression for fringe width in oung’s double slit e9eriment. +etch the

intensity distribution of this interference attern.

OR

What do you mean by diffraction of light? +tate the basic condition for diffraction of

light to tae lace.

Deri)e an e9ression for the width of central ma9imum in the diffraction attern of asingle slit. +etch the intensity distribution of this diffraction attern.

!#. Draw a labeled diagram of an astronomical telescoe. Write e9ressions for its resol)ing

ower and magnifying ower.

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n astronomical telescoe uses an ob&ecti)e lens of focal length 1* m and eye lens of

focal lengths 2 cm. the diameter of ob&ecti)e lens is 1# m. What is resol)ing ower andmagnifying ower.

E"ae mean wa)elength 91# -$ m.F

OR

Draw a labeled diagram of a comound microscoe. Write e9ressions for its resol)ing

and magnifying owers. "he focal lengths of ob&ecti)e and eye lens of a comound

microscoe are 2 cm and * cm resecti)ely. "he tube length is cm. What is its

magnifying ower?

Ajay Sharma

: Mob :- 3(1(!#31, Email :- [email protected];

JIVEM JHUJHUNU (RAJ.)

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4254ajay Sharma Paper