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aieee is on 27th april, for ur info.

cutoffs are gonna be higher this year than 2007 , i expect.

hey,

2007 highest was 429 / 486.

this is really not worth even calling a joke.

great harshavardhan260.

u are gonna be within top 300 anyways.

and even top 50 , if god wishes

thanks to all who posted on this thread.

now i am an NTS scholar.

Karan Singh.

| P | = 10 D
P = 10 ( convex ) or P = -10 ( concave )

P = 1/f

f = 1/10 m = 10 cm (convex)
OR f= 1/-10m = -10cm (concave)

convex lens
------------------
mirror formula
u is unknown
v = -5 ( its a lens )
f = 10

u = -10/3

concave lens
----------------
mirror formula
u is unknown
v = -5 ( its a lens )
f = -10

u = -5

thats the answer

answer is -10/3 for convex lens and -5 for concave lens

from the first case,
applying magnification and mirror formula, we get f = +60cm.

the we use again magnification and mirror formula taking u = -3v,
we get u = -120 cm which is req answer.

hi ankur,

i would say schand for PCM.

for jee ( i too am in X ),
for early preparation stage ( such as the stage i and u r in),
physics - resnick and halliday ( classic and interesting too )
maths - try out class XI math stuff, u can have plane trignometry by s l loni.
chem - university chemistry ( Bruce. H. Mahan ) ( good book )

maths u can go for RD Sharma or RL Arora.
both are equally good.

chem could be s chand or pradeep.

m= h_i/ h_o= - v /u ( u must be knowing that as u r in class x )

v = - u.h_i / h_o

as per ur ques, absolute( h_i / h_o) is 1 / 2. but image an only be smaller in concave mirror when it is real. so h_i/h_o is -1 / 2 as image is inverted.

v = - ( - 10 )x(-1/2)
= - 5 cm.

so image is 5 cm in front of mirror ( -ve side ).

Please Note
above answer given by DECODER is wrong bcoz he takes m = 2.
2 reasons why its wrong:

1. if image is 20 cm behind the mirror (+ve) , it is virtual. which means h_i

h_ofor a conacve mirror. but the question says h_i = h_o / 2.

2. h_i < h_o is possible in a concave mirror only when absolute( v ) < absolute( u ).

rate me if u found it useful and if it resolved ur queries.

by the way, i too am in class X

einstein is the WINNER for me

if they have the DAMN spirit, fight with us FACE to FACE.

i do not think

it is quite fine ( on easier side )

Calculus by I A Maron
or By G. N. Berman

Both are problem books.

conti spect is spectrum of em waves, all frequencies are present.