CLASS-12(CBSE AND STATE BOARDS OF BIHAR AND JHARKHAND)
PHYSICS OPTICS
2 MARKS QUESTION:
Q1) WHERE SHOULD AN OBJECT BE PLACED FROM A CONVEX LENS TO FORM AN IMAGE OF THE SAME SIZE?CAN IT HAPPEN IN CASE OF CONVEX LENS?
ANS)AT A DISTANCE OF 2f FROM THE LENS.NO IT CANNOT HAPPEN FOR CONVEX LENS.
Q2)WHY DOES A RISING SUN APPEAR BIGGER?
ANS-LIGHT FROM THE RISING SUN REACHES THE EARTH OBLIQUELY THROUGH DIFFERENT PART'S OF THE EARTH'S ATMOSPHERE SUFFERING A UNEQUAL REFRACTIONS. THE VERTICAL DIAMETER APPEARS SHORTER AND HORIZONTAL DIAMETER APPEARS BIGGER. THEREFORE,THE RISING SUN APPEARS OVER.
Q3) WHAT ARE THE TWO ESSENTIAL CONDITIONS FOE TOTAL INTERNAL REFLECTION?
ANS-TWO ESSENTIAL CONDITIONS FOR TOTAL INTERNAL REFLECTION ARE:
1)LIGHT SHOULD TRAVEL FROM A DENSER MEDIUM TO A RARER MEDIUM.
2)ANGLE OF INCIDENCE IN DENSER MEDIUM SHOULD BE GREATER THAN THE CRITICAL ANGLE FOR THE PAIR OF MEDIA IN CONTACT.
Q4)WHAT IS POWER OF A LENS?WHAT IS ITS S.I UNIT?
ANS-IT IS THE ABILITY OF THE LENS TO CONVERGE A BEAM OF LIGHT FALLING ON THE LENS. ITS S.I UNIT IS DIOPTRE(D).
Q5) A GLASS SLAB IS PLACED OVER A PAGE IN WHICH LETTERS LETTERS ARE PRINTED IN DIFFERENT COLOURS. WILL THE IMAGE OF IMAGE OF ALL THE LETTERS LIE IN THE SAME PLANE ?
ANS-REFRACTIVE INDEX µ OF GLASS IS DIFFERENT FOR DIFFERENT COLOURS THEREFORE THEY WILL NOT LIE IN THE SAME PLANE.
Q6) WHY ARE DANGER SIGNALS RED IN COLOUR ?
ANS-SINCE THE WAVELENGTH OF RED IS LARGEST IN THE VISIBLE REGION IN THE VISIBLE REGION,THEREFORE IT IS LEAST SCATTERED .SO IT CAN BE SEEN FROM A LARGE DISTANCE.
Q7)WHAT IS MAGNIFYING POWER OF A MICROSCOPE?
Q8)WHAT IS RESOLVING POWER OF A LENS?
Q9)WHAT IS A WAVEFRONT?
Q10)WHAT IS SUPERPOSITION PRINCIPLE?
WHAT ARE COHERENT SOURCES OF LIGHT?
Q11)WHAT ARE THE CONDITIONS FOR SUSTAINED INTERFERENCE?
Q12)IN YOUNGS DOUBLE SLIT EXPERIMENT,IF SLITS S1 AND S2 ARE ILLUMINATED BY 2 BULBS OF SAME POWER,WHAT WILL BE OBSERVED ON THE SCREEN?
ANS)NO INTERFERENCE PATTERN WILL BE OBSERVED BECAUSE BECAUSE WAVES REACHING AT ANY POINT ON THE SCREEN DONOT HAVE CONST. PHASE DIFFERENCE.(THE 2 BULBS ARE INCOHERENT).
Q13)WHY IS INTERFERENCE NOT DETECTED ,WHEN THE TWO COHERENT SOURCES ARE FAR APART?
ANS- FRINGE WIDTH ß IS INVERSELY PROPORTIONAL TO THE DISTANCE d BETWEEN THE 2 SLITS.
Q14)DEFINE DIFFRACTION?WHAT IS THE WIDTH OF CENTRAL MAXIMUM IN DIFFRACTION DUE TO A SINGLE SLIT.
Q15)WHAT IS THE DIFFERENCE BETWEEN DIFFRACTION AND INTERFERENCE?
Q16)"LIGHT IS TRANSVERSE IN NATURE"
THIS STATEMENT CAN BE PROVED BY WHICH OF THE FOLLOWING?
A)INTERFERENCE
B)DIFFRACTION
C)POLARISATION
ANS)POLARISATION.
Q17)DEFINE BREWSTERS AND MALUS LAW?
Q18)WHAT ARE POLAROIDS.GIVE ITS USES?
LONG ANS QUESTIONS:
Q19)EXPLAIN DIFFRACTION DUE TO A SINGLE SLIT WITH DIAGRAM.HENCE FIND THE WIDTH OF THE CENTRAL BRIGHT FRINGE.
Q20)STATE HUYGENS PRINCIPLE AND PROVE THE LAWS OF REFRACTION ON THE BASIS OF WAVE THEORY?
Q21)WHAT IS FRNGE WIDTH?DERIVE AN EXPRESSION FOR IT?
Q22)DERIVE CONDITIONS FOR CONSTRUCTIVE AND DESTRUCTIVE INTERFERENCE?
Q23)EXPLAIN THE WORKING OF CASSEGRAIN TELESCOPE WITH DIAGRAM?
Q24)DRAW A LABELLED DIAGRAM OF COMPOUND MICROSCOPE?
Q25)DESCRIBE AN ASTRONOMICAL TELESCOPE AND DERIVE EXPRESSION FOR ITS MAGNIFYING POWER?
Q26)STATE AND PROVE PRISM FORMULA?EXPLAIN WITH GRAPH
Q27)DERIVE LENS MAKERS FORMULA FOR CONVEX LENS?
Q28)EXPLAIN REFRACTION FROM DENSER TO RARER MEDIUM AT A CONVEX SPHERICAL REFRACTING SURFACE?
PHYSICS OPTICS
2 MARKS QUESTION:
Q1) WHERE SHOULD AN OBJECT BE PLACED FROM A CONVEX LENS TO FORM AN IMAGE OF THE SAME SIZE?CAN IT HAPPEN IN CASE OF CONVEX LENS?
ANS)AT A DISTANCE OF 2f FROM THE LENS.NO IT CANNOT HAPPEN FOR CONVEX LENS.
Q2)WHY DOES A RISING SUN APPEAR BIGGER?
ANS-LIGHT FROM THE RISING SUN REACHES THE EARTH OBLIQUELY THROUGH DIFFERENT PART'S OF THE EARTH'S ATMOSPHERE SUFFERING A UNEQUAL REFRACTIONS. THE VERTICAL DIAMETER APPEARS SHORTER AND HORIZONTAL DIAMETER APPEARS BIGGER. THEREFORE,THE RISING SUN APPEARS OVER.
Q3) WHAT ARE THE TWO ESSENTIAL CONDITIONS FOE TOTAL INTERNAL REFLECTION?
ANS-TWO ESSENTIAL CONDITIONS FOR TOTAL INTERNAL REFLECTION ARE:
1)LIGHT SHOULD TRAVEL FROM A DENSER MEDIUM TO A RARER MEDIUM.
2)ANGLE OF INCIDENCE IN DENSER MEDIUM SHOULD BE GREATER THAN THE CRITICAL ANGLE FOR THE PAIR OF MEDIA IN CONTACT.
Q4)WHAT IS POWER OF A LENS?WHAT IS ITS S.I UNIT?
ANS-IT IS THE ABILITY OF THE LENS TO CONVERGE A BEAM OF LIGHT FALLING ON THE LENS. ITS S.I UNIT IS DIOPTRE(D).
Q5) A GLASS SLAB IS PLACED OVER A PAGE IN WHICH LETTERS LETTERS ARE PRINTED IN DIFFERENT COLOURS. WILL THE IMAGE OF IMAGE OF ALL THE LETTERS LIE IN THE SAME PLANE ?
ANS-REFRACTIVE INDEX µ OF GLASS IS DIFFERENT FOR DIFFERENT COLOURS THEREFORE THEY WILL NOT LIE IN THE SAME PLANE.
Q6) WHY ARE DANGER SIGNALS RED IN COLOUR ?
ANS-SINCE THE WAVELENGTH OF RED IS LARGEST IN THE VISIBLE REGION IN THE VISIBLE REGION,THEREFORE IT IS LEAST SCATTERED .SO IT CAN BE SEEN FROM A LARGE DISTANCE.
Q7)WHAT IS MAGNIFYING POWER OF A MICROSCOPE?
Q8)WHAT IS RESOLVING POWER OF A LENS?
Q9)WHAT IS A WAVEFRONT?
Q10)WHAT IS SUPERPOSITION PRINCIPLE?
WHAT ARE COHERENT SOURCES OF LIGHT?
Q11)WHAT ARE THE CONDITIONS FOR SUSTAINED INTERFERENCE?
Q12)IN YOUNGS DOUBLE SLIT EXPERIMENT,IF SLITS S1 AND S2 ARE ILLUMINATED BY 2 BULBS OF SAME POWER,WHAT WILL BE OBSERVED ON THE SCREEN?
ANS)NO INTERFERENCE PATTERN WILL BE OBSERVED BECAUSE BECAUSE WAVES REACHING AT ANY POINT ON THE SCREEN DONOT HAVE CONST. PHASE DIFFERENCE.(THE 2 BULBS ARE INCOHERENT).
Q13)WHY IS INTERFERENCE NOT DETECTED ,WHEN THE TWO COHERENT SOURCES ARE FAR APART?
ANS- FRINGE WIDTH ß IS INVERSELY PROPORTIONAL TO THE DISTANCE d BETWEEN THE 2 SLITS.
Q14)DEFINE DIFFRACTION?WHAT IS THE WIDTH OF CENTRAL MAXIMUM IN DIFFRACTION DUE TO A SINGLE SLIT.
Q15)WHAT IS THE DIFFERENCE BETWEEN DIFFRACTION AND INTERFERENCE?
Q16)"LIGHT IS TRANSVERSE IN NATURE"
THIS STATEMENT CAN BE PROVED BY WHICH OF THE FOLLOWING?
A)INTERFERENCE
B)DIFFRACTION
C)POLARISATION
ANS)POLARISATION.
Q17)DEFINE BREWSTERS AND MALUS LAW?
Q18)WHAT ARE POLAROIDS.GIVE ITS USES?
LONG ANS QUESTIONS:
Q19)EXPLAIN DIFFRACTION DUE TO A SINGLE SLIT WITH DIAGRAM.HENCE FIND THE WIDTH OF THE CENTRAL BRIGHT FRINGE.
Q20)STATE HUYGENS PRINCIPLE AND PROVE THE LAWS OF REFRACTION ON THE BASIS OF WAVE THEORY?
Q21)WHAT IS FRNGE WIDTH?DERIVE AN EXPRESSION FOR IT?
Q22)DERIVE CONDITIONS FOR CONSTRUCTIVE AND DESTRUCTIVE INTERFERENCE?
Q23)EXPLAIN THE WORKING OF CASSEGRAIN TELESCOPE WITH DIAGRAM?
Q24)DRAW A LABELLED DIAGRAM OF COMPOUND MICROSCOPE?
Q25)DESCRIBE AN ASTRONOMICAL TELESCOPE AND DERIVE EXPRESSION FOR ITS MAGNIFYING POWER?
Q26)STATE AND PROVE PRISM FORMULA?EXPLAIN WITH GRAPH
Q27)DERIVE LENS MAKERS FORMULA FOR CONVEX LENS?
Q28)EXPLAIN REFRACTION FROM DENSER TO RARER MEDIUM AT A CONVEX SPHERICAL REFRACTING SURFACE?
