March 2011 - Career Point

37. Two blocks are connected by a massless string
through an ideal pulley as shown. A force of 22N is
applied on block B when initially the blocks are at
rest. Then speed of centre of mass of block A and
block B, 2 sec, after the application of force is
(masses of A and B are 4 kg and 6 kg respectively
and surfaces are smooth) –
A
4kg
B
6kg
(A) 1.4 m/s 2 (B) 1 m/s 2
(C) 2 m/s 2
(D) None of these
F = 22 N
38. A chain of length 1.5 πR and mass ‘m’ is put on a
mounted half cylinder as shown in figure. Chain is
pulled by vertically downward force 2 mg. Assuming
surfaces to be friction less, acceleration of chain is –
R
θ
1.0 m
O
(A) 10.2 N upwards (B) 4.2 N downwards
(C) 8.3 N downwards (D) 6.2 N upwards
CHEMISTRY
1. According to Bohr’s theory, angular momentum of
an electron in fourth orbit is -
h h 2h
4h
(A) (B) (C) (D)
2π 4π π
π
2. 1.25g of a solid dibasic acid is completely neutralized
by 25 ml. of 0.25 molar Ba(OH) 2 solution. Molecular
mass of the acid is -
(A) 100 (B) 150 (C) 120 (D) 200
3. Rates of effusion of hydrogen and deuterium under
similar conditions are in the ratio -
(A) 1 : 1 (B) 2 : 1 (C) 2 : 1 (D) 1 : 4
(A) 2g
(B)
2g
3
(C) 2
g
F = 2mg
5g
(D) 3
4. For equilibrium NH 4 HS(s) NH 3 (g) + H 2 S(g)
K C = 1.8 × 10 –4 at 298 K. The value of K p at 298 K
is-
(A) 0.108 (B) 4.4 × 10 –3
(C) 1.8 × 10 –4 (D) 4.4 × 10 –4
39. In hydraulic press radii of connecting pipes r 1 and r 2
are in ratio 1 : 2. In order to lift a heavy mass M on
larger piston, the small piston must be pressed
through a minimum force f equal to -
f
M
(A) Mg
(C) Mg/4
(B) Mg/2
(D) Mg/8
40. A uniform rod of length 2.0 m specific gravity
0.5 and mass 2 kg is hinged atone end to the bottom
of a tank of water (specific gravity = 1.0) filled upto a
height of 1.0 m as shown in figure. Taking the case
θ ≠ 0º the force exerted by the hinge on the rod is :
(g = 10 m/s 2 ) –
5. Given that H 2 O (l) → H 2 O(g) ; ∆H = + 43.7 kJ
H 2 O (s) → H 2 O (l) ; ∆H = + 6.05 kJ
∆H sublimation of ice is -
(A) 49.75 kJ mol –1 (B) 37.65 kJ mol –1
(C) 43.7 kJ mol –1 (D) – 43.67 kJ mol –1
6. Which of the following is a Lewis base ?
(A) CO 2 (B) BF 3
(C) Al 3+ (D) CH 3 NH 2
7. The solubility product K sp of sparingly soluble salt
Ag 2 CrO 4 is 4 × 10 –12 . The solubility of the salt is -
(A) 1 × 10 –12 M (B) 2 × 10 –6 M
(C) 1 × 10 –6 M (D) 1 × 10 –4 M
8. Which of the following chemical reactions depicts
the oxidising behaviour of H 2 SO 4 ?
(A) 2HI + H 2 SO 4 → I 2 + SO 2 + 2H 2 O
(B) Ca(OH) 2 + H 2 SO 4 → CaSO 4 + 2H 2 O
(C) NaCl + H 2 SO 4 → NaHSO 4 + HCl
(D) 2PCl 5 + H 2 SO 4 → 2POCl 3 + 2HCl + SO 2 Cl 2
XtraEdge for IIT-JEE 83
MARCH 2011