for 11 th phy lovers

try doing this if u ve free time

1)
two mirrors are inclined at an angle θ
find the no of images formed

2)
a person enters a room with ceiling and 2 adjacent walls as mirrors .
how many images can he see ?

28 Answers

9
Celestine preetham ·

hmm i know the formula but the derivation is tricky

ill be waiting for sunday ( b5555 ;) )

1
Ankit Tripathi ·

No of Images will be calculated by (360/c)-1 where c is the angle between the two mirrors.

1
Rohan Ghosh ·

yes i have talked of a specific case ..

9
Celestine preetham ·

but rohan see #11 there are diff cases

1
Rohan Ghosh ·

in other words they form a polygon

1
Rohan Ghosh ·

the first one can be analysed by observing that betweeen any three images angle 2θ between any five angle 4θ ... ultimately when they coincide we get 2π/θ but the object is to be not considered so we get 2π/θ - 1

9
Celestine preetham ·

no ram see #20

1
Pavithra Ramamoorthy ·

3 images each of d wall n ceilin are visible.............. rit???

9
Celestine preetham ·

any tries now ???

1
sriraghav ·

sorry! i didnt see the ceiling!!

9
Celestine preetham ·

no for second one its 7 of which 6 are visible

1
sriraghav ·

answer for 1st is a standard one...'
for second one it is 2, though 3 images r formed only 2 are visible

1
Anuj ·

it is given in 9th standard book of ICSE...i have forgotten ans...

33
Abhishek Priyam ·

Derivation..

is it not obvious by simple observations.. :)

62
Lokesh Verma ·

I have not known a single book which gives the correct explanation for part 1 of this question! :)

But this is worth thinking in free time only :)

1
Ritika ·

oh yea.......xtreme case of non-attentionitis.

33
Abhishek Priyam ·

lol..

where it is fraction...

theres [] hai naa...gr8est integer function...

1
Ritika ·

ab dekho, mujhe kabhi phy6 aur math mein logic saath nahi deta...
but how can no. of images be a fraction?

33
Abhishek Priyam ·

But it will be better to do from the basic because itna yaad nahi rahta :(

33
Abhishek Priyam ·

1st one..

case 1.
If 360/θ is even...
then no of images= 360/θ-1

case 2.
If 360/θ is odd
2.1 object at angle bisector
then no of images=360/θ
2.2 object not at angle bisector
no of images =360/θ-1
case 3.
if 360/θ is fraction then
no of images [360/θ]

39
Dr.House ·

for 1st one if no one gives explanation by sunday, i will. i have a beautiful explanation, trust me.

13
Двҥїяuρ now in medical c ·

2nd one

infinite numbers of images theoretically

but a few practically

39
Dr.House ·

late post tha............. by the way, abhirup formula nahiin try to derive it, and ya its only for 11th waale.

39
Dr.House ·

@ritika, it does not depend on the placement of object { in a way depends but not here]. u only have to...........

33
Abhishek Priyam ·

Power Cut :(

13
Двҥїяuρ now in medical c ·

[\frac{2\Pi}{\theta } -1]

33
Abhishek Priyam ·

1st one...

mere ko result pata hai.. post karun kya...

1
Ritika ·

wer's d object placed in the 1st question?
Nd i'll assume d person is luminiscent...;)

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