Answers of the Physics Exam

[Mysteryagr]

الفيزياء باللغة الأنجليزية

Question 1:
Firtsly: Scientific idea
1- Mutual induvtion between two coils
2- Messiner Effect
3- Pascal's principle
4- The active medium must be in the state of population inversion
Emission of radiation for the excited atom through the stimulated emission.
Amplification by stimulated emission through the resonant cavity

Secondly:
(A) Factors:
1- Kind of medium , Temperture
2- Magnetic flux density , electric current intensity ,
area of the coil , number of turns of the coil
3- Delta Y = ( wave legnth x R )/d , decreasing distance seprating two slits
using red light of great wave length ;
two successive frings increasing by increasing the wave length

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Question 2:
Firstly : what is meant by:
1-Avogadro's number is the number of particles found in one mole of a substance.
It is the number of atoms in exactly 12 grams of carbon-12.
This experimentally determined value is approximately 6.022 x 1023 particles per mole.
2- 300 is the ratio between collector and base currents in a transistor.
3-0.5 volt is the induced emf generated in the same coil due to the change of current
passing in the coil by rate 1 amp/sec
4- At constant pressure the unit volume of a gas increase by 1/273 if the temperture
rises from 0 C to 1 C

Secondly :
(A) Compare:
1- Leyman's series: Ultra violet range,
short wave length
Balmer's series : Visible range
longer wave length

2- Spontaneous emission: Ocurrs when excited atom relaxes and transfers to the ground
state after life time is over ( show by drwaing )
Stimulated emission : Occurs when incident photon falls by ecited atom before life time
is over ( show by drawing )

3- Amp. R.H.R: Determines direction of magnetic field arround a stright wire
carrying current
Fleming R.H.R: determine direction of induced current in striagt wire
moving in a magnetic field