## King 3 years ago A convex mirror of focal length f produces an image half of the size of the object. What is the distance of the object from the mirror?

Use lens formula

2. King

1/v-1/u=1/f? that one?

Object distance = -u image distance = v Height of image / height of object = v/u

4. King

hi/ho=-v/u

5. King

can u do it?

yeah

7. King

yeah as in can u post the sol.?

see now, h / 2h = v/u u = 2v

9. King

ok

\[1divv -1divu =1divf\]

11. King

\[1/v-1/u=1/f\]

|dw:1332858999064:dw|

13. King

why is it -2v?

Becoz, in calculation, u should take object distance as negative. So, u becomes -u. And hence -2v

15. King

ok so u get 3/2v=1/f 2v=3f

16. King

after that?

17. King

Then, equate v = 3f / 2

Substitute it in the formula: 1/v - 1/u = 1/f

20. King

i get u=3f

U r correct

22. King

so that it?

23. King

Yeah, soorry. Then don't use - 2v in the formula. use 2v. U may get it.

25. King

i get u=f

26. King

ok.thnx gtg!1

27. King

bye

Oooooooooooo. Gtg. Byeeeeeeeeeee. ur result?

29. King

in what 9th .....94.83%

30. King

kk bye!

Super. Congrtas. Ready for US trip?????????????

32. King

yup!

PLz reply to my email. plzzzzzzzzzzz

34. King

ok

Byeeeee

36. salini

@aadarsh, u have successfully completed 10th so tell me, can a convex mirror produce an image which is half of the object's height?

Arre Shalini didi and king, I think I was in a dream while solving this question. I thought it to be a convex lens instead of a mirror. Here is the detailed answer. Sorry for mistake.

Mirror Formula: 1/v + 1/u = 1/f And, h'/h = -v/u (magnification formula) So, given, h'/h = -v/u = 1/2............(i) So, u = -2v.......(ii) Now, 1/v + 1/(-2v) = 1/f Or, 1/2v = 1/f Or, f = 2v Or, f = 2v So, f = -u [From (ii)]

39. salini

u havent answered my question yet aadarsh can a convex mirror , produce an image which is half of the object's height? i wud like to add one thing here be very clear to visualise the ray diagrams for any lens or mirror b4 solving sum

@salini akka, i think a convex mirror can produce an image half size of that of object, in some cases, when object is between infinity and pole of mirror.

41. salini

oh my! check ur 10th book aadarsh

didi, its given that it will form a diminished, virtual and erect image. That's all na?????????

43. salini

ya so will it produce a half-sized image?

not really. BUt can it not produce in some cases???????????????

45. salini

i am curious when? when our bible says no it is a no u know wat i mean by bible dont u?

Yeah, "Bible" means Book. (NCERT) Can u plz say why it cannot?

47. salini

its the property of convex mirror to always form virtual diminished(not even the quarter of size of object)_ how? it was found by great ppl all we do is read them right?

48. salini

whenever u see a question related to lens or mirrors flash the image formation diagrams b4 the formula @king ur question is wrong

How didi? question is wrong? See my process . Everything is correct. But u r true taht a convex mirror cannot form an half image image.

50. salini

:) see ur text book and read my last comment it will help u

Yeah, u r rite didi. I was mad at the first itself.

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