1. Xtra Edge February 2012 - Career Point

18. A light ring which can slip frictionlessly over wire is
slipped over wire. When a tuning fork start
resonating with wire, ring is found to be at rest at a
distance 15 cm from one end. If velocity of wave in
wire is 10 m/s, minimum frequency of tuning fork is-
(A) 50 Hz (B) 60 Hz
(C) 70 Hz (D) None of these
19. Now two light rings are slipped on wire which can
move frictionlessly. When wire is plucked, the two
rings are found to be at rest separated by 12 cm.
Maximum wavelength of wave in wire is -
(A) 4 cm (B) 8 cm
(C) 12 cm (D) 24 cm
This section contains 3 questions (Questions 20 to 22).
Each question contains statements given in two columns
which have to be matched. Statements (A, B, C, D) in
Column I have to be matched with statements (P, Q, R, S)
in Column II. The answers to these questions have to be
appropriately bubbled as illustrated in the following
example. If the correct matches are A-P, A-S, B-Q, B-R,
C-P, C-Q and D-S, then the correctly bubbled 4 × 4
matrix should be as follows :
P Q R S
A P Q R S
B P Q R S
C P Q R S
D P Q R S
Mark your response in OMR sheet against the question
number of that question in section-II. + 6 marks will be
given for complete correct answer and No Negative
marks for wrong answer. However, 1 mark will be
given for a correctly marked answer in any row.
20. A small ring of mass m passes through a smooth wire
bent in form of horizontal circle. The ring is
connected to a spring whose other end is fixed at A
on the wire as shown. The natural length of spring is
mg
R and spring constant is where m is mass of the
R
ring and R is also the radius of circle. Initially the
ring is released from rest from position B and it
moves towards C as in the figure. (N = Normal
reaction between wire and ring, v = speed of ring)
C
wire
A
60º
Column-I Column-II
(A) N = mg (P) at position B
(B) N = zero (Q) at position C
(C) N = 2 mg (R) some where between
position B and position C
(D) v = gR (S) never
B
21. A body of mass ‘m’ is acted upon by net force F r .
r and v be their initial position and velocity. All
quantity are in S.I. unit . Then match the following.
Column-I Column-II
2
(A) F = −4x
î , r = 0 , (P) Motion : S.H.M.
v = 2î,
m = 2
(B) j ˆ
F = ( 2 − 4y)
, r = 0 (Q) Motion : Non-periodic
v = 0 , m = 1
3
(C) F = − 2(
x + x ) î , (R) Path : Straight line
XtraEdge for IIT-JEE 62 FEBRUARY 2012
– 2
r = 10 î v = 0 , m = 1
(D) F = − 4(
xî
+ yjˆ
)
j
(S) Time period : π
ˆ r = 2 , v = 6î,
m = 1
22. The cubical container filled with water is given
acceleration →
a = a0 î + a0 j ˆ + a0 k ˆ , then : (neglect
the effect of gravity)
E F
C
H
D
G
B
A z
Column-I Column-II
(A) Pressure at point A is (P) less than pressure
at point G
(B) Pressure at point D is (Q) less than pressure
at point F
(C) Pressure at point E is (R) Greater than
pressure at point C
(D) Pressure at point H is (S) Greater than pressure
at point B
CHEMISTRY
Questions 1 to 9 are multiple choice questions. Each
question has four choices (A), (B), (C) and (D), out of
which ONLY ONE is correct. Mark your response in
OMR sheet against the question number of that
question. + 3 marks will be given for each correct
answer and – 1 mark for each wrong answer.
1. Which of the substance has maximum number of
hydrogen atoms per gm of the substance ?
At. wts. : Cu – 63.5 ; S – 32 ; O –16 ; H –1
(A) CH4 (B) CuSO4 . 5H2O
(C) H2O2 (D) H2O
y
x