optics

as eureka stated lets put up some problemss that might be of good help for jee 2009 revision aspect. i just did not want to mix it up with his thread and make it go unnoticed like my chemistry hub

1}show that the focal length of a thin lens is not changed when the lens is rotated so that the left and right surfaces are interchanged.

2}As an object is moved from the surface of a thin converging lens to a focal point, over what range does the image distance vary?

3}two thin similar convex glass poeces are joined together front to front, eith its rear portion silvered such that a sharp image is formed 0.2 m for a object at infinity. when the air between the glass pieces is replaced by water{μ=4/3}, find the position of the image.

47 Answers

33
Abhishek Priyam ·

velocity of image parallel to m1... kaha hai...

1
skygirl ·

yup. power cut!

11
Subash ·

power cut [7]

1
skygirl ·

power cut ho gaya tha...

abhi aya...

the light doesnt come from the first image for the second mirror subhash... because its a virtual image...

it just appears to come from there...

1
skygirl ·

q.4) is the ans vcos2θ ??

39
Dr.House ·

for 4 th one answer is 2vsinθ

39
Dr.House ·

8 th one answer is - 1/2

1
skygirl ·

no said wrong... trigo prob !! bad mistake ..

33
Abhishek Priyam ·

Q.4 2vsinθ

33
Abhishek Priyam ·

din saw that he replied.. :P

1
skygirl ·

1
skygirl ·

2vsinθ bhi mila mereko... but why is this wrong ???

11
Subash ·

hey now the second object should be the first one right

light comes from the object so u2=-f

do u have anything against this

1
skygirl ·

kk... yeh sahi hai... isiliye we resolve the horizontal one :)
thanx:)
then 2vsinθ.. :)

33
Abhishek Priyam ·

[1][3]

1
skygirl ·

[3]

11
Subash ·

ok sky akka now got it

1
skygirl ·

akka @!$#$^$& ?????????

11
Subash ·

akka is didi in tamil!

24
eureka123 ·

hay i already solved Q4 in my first post here...........................[3][3][3][3]

3
msp ·

the forth one is solved by prashanth sir.

24
eureka123 ·

where dear????????[7][7]....see post no.6 here

24
eureka123 ·

yippe....my Q8 also correcct[1]

3
msp ·

62
Lokesh Verma ·

I am myself not convinced aobut Q4. (I mean I dont think I understood that one.)

About Q8, I have to see it fully.. first look seems corect!

39
Dr.House ·

5} an isotropic point source is placed at a depth `h` below the water surface.Afloating opaque disc is placed on the surface of water so that the bulb is not visible from the surface. What is the minimum radius of the disc? take refractive index of the water=μ.

6} a ray of light falls normally on a refracting face of a prism.find the angle of the prism if the ray just fails to emerge from the prism.(μ=3/2)

7}The refractve index of the material of a prism of refracting angle 45 degrees is 1.6 for a certain monochromatic ray.What will be the minimum angle of incidence of this ray on the prism so that no total internal reflection takes place as the ray comes out of the prism.

8}two thin converging lenses are placed on a common axis, so that the centre of one of thjem coincides with the focus of the other.An object is placed at a distance twice the focal length from the left hand lens. where will the image be? what is the lateral magnification? the focal length of each lens is `f`.

9}The refracting angle of a glass prism is 30 degrees. A ray is incident onto one of the faces perpendicular to it. Find the angle δ between the incident ray and the ray that leaves the prism. the refractive index pf the prism is μ.

10}A solid glass sphere with radius R and an index of refraction 1.5 is silvered over one hemisphere. a small object is located on the axis of the sphere at a distance 2r to the left of the vertex of the unsilvered hemisphere. find the position of the final image after all refractions and reflections that have taken place.

39
Dr.House ·

TRUST ME, THESE ARE NOT DIFFICULT ONES, RATHER THE CONCEPTUAL ONES. EACH AND EVERYONE TESTS A CONCEPT OF OPTICS IN ITS OWN WAY.

IF U DONT GET THESE DONT GET FRUSTATED, RATHER HAVE A GOOD LOOK AT THE FORMULAE AND CONCEPTS ONCE AGAIN AND GIVE A SECOND TRY.... I AM SURE U WILL SUCCEEED...

62
Lokesh Verma ·

Try these questions.. osme of them are really good :)

Dont go by the past record of Bhargav's unsolvable problems.. They are pretty relevant for IIT JEE

24
eureka123 ·

Q4 i hope its correct

24
eureka123 ·

Q5

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