WBJEE Model Questions
Ques
The centre of mass of a solid cone along the line from the centre of the base to the vertex is at
a) One – fifth of the height
b) One – fourth of the height
c) One – eight of the height
d) One – third of the height
Ques
The ratio of the radii of gyration of a circular disc to that of circular ring, each of same mass and same radius about their axes is
a) √2:√3
b) √3:√2
c) √2:1
d) 1:√2
Ques
If a solid sphere and solid cylinder of same mass and radius rotate about their own axis the moment of inertia will be greater for
a)Solid cylinder and solid sphere
b) Solid sphere
c) Solid cylinder
d) Both solid cylinder and solid sphere are equal
Ques
A rod of length 1.4 m and negligible mass has two masses of 0.3 kg and 0.7 kg tied to its two ends. Find the location of the point on this rod, where the rotational energy is minimum when the rod is rotated about the point.
a) 0.7mfrom0.7kg
b) 0.7mfrom0.3kg
c) 0.98mfrom0.3kg
d) 0.98mfrom0.7kg
Ques
Two racing cars of masses m1 and m2 are moving in circles of radii r1 and r2 respectively. Their speeds are such that each makes a complete circle in the same time t. The ratio of the angular speeds of the first to the second car will be
a) R1 : r2
b) M1: m2
c) M1 m2: r1 r2
d) 1 : 1
Ques
Arrange the following cations in decreasing order of stability:
a) iii > i > iv > ii
b) i > ii > iv > iii
c) ii > iii > i > iv
d) i > iii > ii > iv
Ques
Number of isomers with molecular formula C H
Br
is ________.
a) 1
b) 0
c) 2
d) 3
Ques
The correct IUPAC name of the following compound is
a) 2 – methyl – 5 – nitro – 1 – chlorobenzene
b) 2 – chloro – 1 – methyl1 – 4 – nitrobenzene
c) 5 – chloro – 4 – methyl 1 – 1 – nitrobenzene
d) 3 – chloro – l – methyl – 1 – nitrobenzene
Ques
In which of the following molecules all the effects namely inductive, mesomeric, and hyperconjugation operate?
a) 
b) 
c) 
d) 
Ques
The decreasing order of stability of following anions
a) S > P > R > Q
b) Q > R > S > P
c) R > Q > P > S
d) P > Q > R > S
Ques
Which of the following compounds will exhibit d – orbital resonance?
a) 
b) 
c) 
d) 
Ques
Two identical solid spheres each of mass 2 kg and radii 10 cm are fixed at the ends of a light rod. The separation between the centres of the spheres is 40 cm. The moment of inertia of the system about an axis perpendicular to the rod passing through its middle point is __________ × 10-3 kg-m2
Ques
A person driving car at a constant speed of 15 m/s is approaching a vertical wall. The person notices a change of 40 Hz in the frequency of his car’s horn upon reflection from the wall. The frequency of horn is ______ Hz.
Ques
A pole is vertically submerged in swimming pool, such that it gives a length of shadow 2.15 m within water when sunlight is incident at an angle of 30o with the surface of water. If swimming pool is filled to a height of 1.5 m, then the height of the pole above the water surface in centimeters is (nw = 4/3) ____________
Ques
The volume of 0.02 M aqueous HBr required to neutralize 10.0 mL of 0.01 M aqueous Ba(OH)2 is (Assume complete neutralization)
(1) 5.0 mL
(2) 10.0 mL
(3) 2.5 mL
(4) 7.5 mL