21. Which of the following compound is aromatic according to Huckel’s rule ?
22. How many structural isomers are possible for Pentane ?
(A) 2
(B) 3
(C) 0
(D) 1
23. Among the 4 common type of refrigerants which has the highest ozone depletion potential ?
(A) HFCs
(B) LTCs
(C) CFCs
(D) HCFCs
24. Monomer units of Nylon 6, 6 are –
(A) Sebacic acid and Terephthalic acid
(B) Terephthalic acid and Methanol
(C) Adipic acid and Hexamethylenediamine
(D) Terephthalic acid and Ethyleneglycol
25. Select the correct statement about thermoseting polymers –
(A) Cross-linking occurs during heating and when it cools it hardens ‘irreversibly.
(B) All of these
(C) melt or soften on heating.
(D) These are cross-linked polymers.
26. Match List-I with List-II and select the correct answer using the code given the lists :
List-I List-II
(i) PVC (a) Thermosettine polymer
(ii) Bakelite (b) Thermoplastic polymer
(iii) Vulcanized (c) Fibre rubber
(iv) Nylon 6 (d) Elastomers
Code
(A) (i) – (a) (ii) – (b) (iii) – (c) (iv) – (d)
(B) (i) – (b) (ii) – (a) (iii) – (c) (iv) – (d)
(C) (i) – (d) (ii) – (b) (iii) – (a) (iv) – (C)
(D) (i) – (b) (ii) – (a), (iii) – (d) (iv) – (C)
27. NH3 has a much higher b.p. than PH3 because
(A) NH3 forms hydrogen bonds
(B) NH3 contains ionic bonds whereas PH3 contains covalent bonds
(C) NH3 has a larger molecular weight
(D) NH3 undergoes umbrella inversion
28. White lead is
(A) Pb(OH)2・2PbCO3
(B) PbSO3・PbO
(C) PbCO3
(D) PbCO3・Pbo
29. Which of the following cells can not produce continuous and constant current for a longer time ?
(A) Daniel cell
(B) Lechlanche cell
(C) Lead accumulator cell
(D) Edison’s cell
30. A lens behaves as diverging lens in air (μ = 1) and converging lens in water (μ = 1.3). The refractive index (μ) of the material of the lens is
(A) μ<1.0
(B) μ= 1.0+1.3/2
(C) 1.0<μ<1.3
(D) μ>1.3
31. I-V graph for a (conductor) metallie wire at two temperatures T1 and T2 is shown in the figure, then –
(A) T1 = T2
(B) Cannot be determined from this graph.
(C) T1> T2
(D) T2> T1
32. An electric motor converts :
(A) Heat energy into mechanical energy.
(B) Eddy currents energy into mechanical energy.
(C) Mechanical energy into electrical energy.
(D) Electrical energy into mechanical energy.
33. The frequency of direct current is :
(A) 100 Hz
(B) 220 Hz
(C) Zero
(D) 50 Hz
34. A ray of light is made incident on a concave mirror, parallel to its principal axis. After reflection it will –
(A) pass through the pole of the mirror
(B) pass through the principal focus
(C) pass through the centre of curvature
(D) move parallel to the principal axis of the mirror
35. If 2A of current is flowing in a conductor from a battery of 5V, then the resistance of the conductor is :
(A) 0.4 Ohm
(B) 10 Ohm
(C) 2 Ohm
(D) 2.5 Ohm
36. A plano convex lens (u = 1.5) with radius of curvature 20 cm is silvered at the curved surface. The power of the system is –
(A) 5 D
(B) 2.5 D
(C) 15 D
(D) 10 D
37. Lenz’s law is a consequence of :
(A) Conservation of energy
(B) Conservation of current
(C) Conservation of charge
(D) Conservation of momentum
38. Which lamp is used as indicator in an electric tester?
(A) Neon lamp
(B) Tungsten lamp
(C) Sodium lamp
(D) Mercury lamp
39. The unit of rate of flow of electric charge is –
(A) Ampere
(B) Ohm
(C) Volt
(D) Mho
40. When white light is incident on a green leaf
(A) all the colours except green are reflected by the leaf.
(B) all the colours are equally absorbed by the leaf.
(C) the green colour is mostly absorbed by the leaf.
(D) the green colour is mostly reflected by the leaf.
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