Cet Mock Test 30th April 2009

CET MOCK TEST Time – 3 Hours

Max. Marks – 450

Instructions:

1.

(i)

The paper has three section Maths, Chemistry and Physics with 50 questions each.

(ii)

The paper consists of 150 question.

(ii)

For each correct response three marks will be awarded and for each incorrect response one mark will be deducted.

r r r r r r Let | a | = 3 and | b | = 4 , then the value of λ for which a + λb and a − λb are perpendicular is given by: (a) −

3 5

(b)

2 3

(c) −

2 3

(d) ±

3 4

2.

If 2x1/3 + 2x −1/3 = 5 , then x is equal to:

3.

(a) 8 or 1/8 (b) 4 or 1/4 (c) 2 or ½ (d) 1 or –1 The solution set of the equation tan(π tan x) = cot(π cot x) is: (a) {0}

4.

5.

6.

(b) φ

(c) {π/4} (d) none of these The period of the function f(x) = sin2x is: (a) 3π / 2 (b) π / 2 (c) π (d) 2π The condition that the roots of the equation px2 – px + q = 0 are in the ratio p : q [q ≠ 0, p ≠ 0] is: (a) 2p + q = 0 (b) p + q = 0 (c) 2p – q = 0 (d) none of these Two persons A and B throw a die alternately till one of them gets a ‘three’ and wins the game. Find their respectively probabilities of winning, if A begins: (a)

1 2 , 3 3

(b)

6 5 , 11 11

(c)

5 4 , 11 11

(d) none of these

7.

1 1 1 If + + = 0 , a b c

1+ a 1 1 1+ b 1

1

1 1 1+ c

(a) –abc (c) 0 8.

(c)

tan(xe x )

π 2 (c) x − π

12.

(d) none of these

(b) symmetric (d) scalar matrix

sin −1 (cos x), 0 ≤ x < 1 , is equal to: (a) x −

11.

(b) tan(xe x )

⎡a h g⎤ The matrix ⎢⎢ h b f ⎥⎥ is: ⎢⎣ g f c ⎥⎦

(a) skew symmetric (c) diagonal matrix 10.

(b) abc (d) none of these

(x + 1)e x ∫ cos2 (xex ) dx is equal to: (a) tan −1 (xe x )

9.

is equal to:

π −x 2 (d) π − x

(b)

The distance between the lines 3x + 4y = 9 and 6x + 8y = 15 is: (a) 3/10 (b) 3/2 (c) 6 (d) none of these 2 If f(x) = x + 1, then the value of fof is equal to: (a) x4 – 2 + 2x2 (b) x4 + 2 + 2x2 (c) x4 + x2 + 1 (d) none of these [x] is equal to: x

13.

lim

14.

(a) 0 (b) 1 (c) –1 (d) does not exist 2 The co-efficient of x in the expansion of (1 + 4x + x2)1/2 is equal to: (a) –2 (b) –3 (c) 2 (d) none of these

15.

x →0

If A = sin2θ + cos4θ, then for all real values of θ: 13 3 13 (a) (b) ≤ A ≤ ≤ A ≤1 16 4 16

(c) 1 ≤ A ≤ 2 16.

The solution of the equation 3 + (a) −1, −

17.

1 5

(d)

3 ≤ A ≤1 4

1 = 2 are: x 1 5 (d) none of these

(b) 0, − 1, −

(c) 2, –1 The probability that a teacher will give an announced test during any class 1 meeting is . If a student is absent twice, then the probability that the student will 5 miss at least one test is: 9 7 (b) 25 75 2 4 (c) (d) 5 5 Two cards are drawn successively with replacement from a pack of 52 cards. The probability of drawing two aces is:

(a)

18.

(a)

1 4 × 12 51

(b)

1 1 × 52 51

1 1 1 1 (d) × × 13 13 13 17 The number of common tangents to the circles x2 + y2 + 2x + 8y – 25 = 0 and x2 + y2 – 4x – 10y + 19 = 0 are:

(c)

19.

(a) 1 (c) 3 20.

(b) 2 (d) 4 r r r r r r The points with position vectors 60i + 3 j, 40i − 8 j and ai − 52 j are collinear if:

(a) a = 40 (c) a = 40

21.

22.

(b) a = –40 (d) none of these The position vectors of point A and B are ˆi − ˆj + 3kˆ and 3iˆ + 3jˆ + 3kˆ respectively. r ˆ + 9 = 0 . The points A and B: The equation of a plane is r ⋅ (5iˆ + 2ˆj − 7k) (a) lie on the plane (b) lie on the same side of the plane (c) lie on the opposite side of the plane (d) none of these The equation of the normal at the point ‘t’ to the curve x = at2, y = 2at is: (a) tx + y = 2at + at3 (b) tx + y = 2at 3 (d) none of these (c) tx + y = at

23.

24.

25.

The equation of the circle which touches the axes of the co-ordinates and the line x y + = 1 and whose centre lies in the first-quadrant is 3 4 (a) 1, 6 (b) 4, 5 (c) 3, 4 (d) 2, 3 A problem in statistics is given to three students whose chances of solving it are 1 1 1 , and . The probability that the problem is solved is: 2 3 4 1 1 (a) (b) 3 2 3 (d) 1 (c) 4 In a equilateral triangle of sides 2 3 cm the circum-radius is: (a) 2 cm (c)

26.

27.

28.

29.

30.

3 cm

(b) 1 cm (d) 2 3 cm

x −1 y − 2 z − 3 x −1 y − 2 z − 3 and are: = = = = 2 4 7 4 5 7 (a) intersecting (b) parallel

The lines

(c) perpendicular The value of 13 C2 + 13C3 + 13C4 + ...... + 13C13 is: (a) 213 – 14

(d) skew

(b) 214 – 14

(c) an even no ≠ 213 − 14 (d) an odd number ≠ 213 − 14 n Cr + 2 nCr–1 + nCr–2 is equal to: (a) n+1Cr (b) nCr+1 (c) n–1Cr+1 (d) none of these Find the equations of the line passing through the point (1, 2, 3) and parallel to the x−6 y−2 z+7 : line = = 12 4 5 x −1 y − 3 z − 3 x −1 y − 2 z − 3 (a) (b) = = = = 12 4 5 12 4 5 x −1 y − 2 z − 4 (d) none of these (c) = = 12 4 5 The A.M. of two number is 34 and G.M. is 16, the numbers are: (a) 64 and 3 (b) 64 and 4 (c) 2 and 64 (d) none of these

31.

In Δ ABC, a = 4, b = 12 and ∠B = 60o, then the value of sinA is: 2 3

(a) (c) 32.

1

34.

35.

36.

37.

(d)

2 3

1 3 2

Maximum value of f(x) = sinx + cosx is: (a) 2 (b) 1 (c)

33.

3 2

(b)

(d) 1 / 2

2

If the difference of two unit vectors is again a unit vector, then angle between them is: (a) 90o (b) 60o (c) 45o (d) 30o The curves y = x2 and 6y = 7 – x3 intersect at the point (1, 1) at an angle: (a)

π 6

(b)

π 3

(c)

π 2

(d)

π 4

cos3 θ − cos 3θ sin 3 θ + sin 3θ + is equal to: cos θ sin θ (a) 0 (b) 5 (c) 3 (d) 1 Area bounded by lines y = 2 + x, y = 2 – x and x = 2 is: (a) 16 (b) 8 (c) 3 (d) 4

The complex number z satisfying the condition arg (a) a parabola (c) a straight line

z −1 π = is: z +1 3

(b) a circle (d) none of these

100 π

38.

If

∫

1 − cos 2x dx = 200k , then k is equal to:

0

(a)

3

(b) (d) π

(c) 2 2 39.

2

3

If n is a positive integer, then n + 2n is divisible by: (a) 2 (b) 3 (c) 5 (d) 6

40.

1 1 1 1 − + − + .... is equal to: 1.2 2.3 3.4 4.5 (a) 4 log 2 – 1 (b) 3 log 2

(c) 2 log 2 – 1

(d) none of these

41.

If f(x) = 1 + αx , α ≠ 0 is the inverse of itself, then the value of α is: (a) 2 (b) –1 (c) –2 (d) 0

42.

The values of x which satisfies both the equations x 2 − 1 ≤ 0 and x 2 − x − 2 ≥ 0 lie in: (a) (1, 2) (b) (–1) (c) (–1, 2) (d) (–1, 1)

43.

The normal to the curve x = a (cosθ + θ sinθ), y = a(sinθ – θ cosθ) at any point θ is such that: (a) it is at a constant distance from the origin (b) it makes a constant angle with x-axis (c) it passes through the origin (d) none of these The range of the function f(x) = [x] – x denotes the greatest integer ≤ x (a) [0, 1) (b) (–1, 0] (c) (–1, 0) (d) none of these

44.

45.

46.

6 + 8i + 6 − 8i is equal to: (a) 3 2i

(b) 2 2 i

(c) 4 2 i

(d) none of these

If the co-efficient of (r + 1)th term in the expansion of (1 + x)2n be equal to that of (r + 3)th term, then: (a) n + r + 1 = 0 (b) n – r – 1 = 0 (c) n – r + 1 = 0 (d) none of these 18

47.

3 ⎞ ⎛ Number of middle terms in ⎜ x − 2 ⎟ x ⎠ ⎝

(a) 4 (c) 2

is: (b) 3 (d) 1

a +π /2

48.

The value of (a)

3π 8

∫a

(sin 4 x + cos 4 x) dx is: (b)

3 2 a π 8

⎛π⎞ (c) a ⎜ ⎟ ⎝2⎠

49.

2

If y = log cos x sin x , then

(d) independent of a dy is equal to dx

(a)

(cot x log cos x + tan x log sin x) (log cos x) 2

(b)

(tan x log cos x + cot x log sin x) (log cos x) 2

(c)

(cot x log cos x + tan x log sin x) (log sin x) 2

(d) none of these

50.

If the radius of the circumcircle of an isosceles triangle PQR is equal to PQ (= PR), then the angle P is: π π (b) (a) 6 3 2π π (c) (d) 3 2

51.

For a reaction M x + + MnO −4 → MO3− + Mn 2+ + 1/ 2O 2 , If 1 mole of MnO −4 oxidises 1.67 moles of Mx+ to MO 3− , the value of x in the reaction is: (a) 1 (c) 3

52.

Which of following is true for a reaction, H 2 O(1) atmospheric pressure? (a) ΔE = 0

53.

54.

(b) 5 (d) 2 H 2 O(g) at 100oC, 1

(b) ΔH = T ΔS

(d) ΔH = 0 (c) ΔH = ΔE The amount of KMnO4 required to prepare 100 ml of 0.1N solution in alkaline medium is: (a) 3.16 g (b) 0.31 g (c) 0.52 g (d) 1.58 g A reaction A2 + B2 → 2AB occurs by the following mechanism in reaction. A2 → A + A ...........(slow) A1 + B2 → AB + B ........(Fast)

55.

A + B → AB .........(Fast) Its order would be: (a) 2 (b) 1 (c) zero (d) 3/2 During electrolysis of fused calcium hydride, the hydrogen is produced at: (a) anode

(b) cathode (c) H2 produced reacts with oxygen to form water (d) Hydrogen is not liberated at all 56.

57.

58.

59.

60.

61.

62.

63.

64.

The oxidation number of S in SO 4−2 is: (a) 0 (b) +8 (c) +6 (d) +4 Magnesium burns in air to give: (b) MgO and Mg3N2 (a) MgCO3 (c) Mg3N2 (d) MgO A radio isotope has a half life of 10 years. What percentage of the original amount of it would you expect to remain after 20 years? (a) 12.5 (b) 25 (c) 8 (d) 0 Iodine is liberated from KI solution when treated with: (b) NiSO4 (a) CuSO4 (c) ZnSO4 (d) FeSO4 The complex [Cr(H2O)4Br2]Cl gives the test for: (b) Cl– (a) Br– (c) Cr3+ (d) Br– and Cl– both The IUPAC name of the compound CH 2 − CH 2 − CH 2 is: | | | CN CN CN (a) 1,2,3-tri cyano propane (b) 3-cyano pentane-1,5 dinitrile (c) 1,2,3-cyano propane (d) 1,2,3-propane tri nitrile Which one is a synthetic polymer? (a) Protein (b) Neoprene (c) Starch (d) Silk Resonance hybrid of benzene is: (a) equally stable as Kekule structures (b) more stable than the Kekule structures (c) less stable than the Kekule structures (d) unpredictable The change in optical rotation (with time) of freshly prepared solutions of sugars is known as: (a) mutarotation (b) rotatory motion

65.

66.

67.

68.

69.

70.

71.

72.

73.

74.

(c) inversion (d) specific rotation Ethane as well as methane can be prepared in single steps from: (a) CH3CHO (b) C2H5OH (d) CH3Br (c) C2H5Br The shape of covalent molecule AX3 is: (a) T-shape (b) triangular (c) pyramidal (d) Any of the above three depending upon the number of lone pairs on A In which of the following binary compound, the ratio rcation/ranion is least? (a) CsF (b) LiF (c) LiI (d) CsI BF3 is a: (a) Bronsted acid (b) Bronsted base (c) Lewis acid (d) Lewis base The rate of a reaction: (a) depends upon temperature (b) is not equal to its molecularity (c) is equal to its molecularity (d) can not be predicted The emf of the cell involving the reaction 2Ag+(aq) + H2(g) → 2Ag(s) 2H+ (aq) is 0.80V. The standard oxidation potential of silver electrode is (a) 0.20 V (b) 0.40 V (c) –0.80 V (d) 0.80 V Copper can be extracted from: (a) kupfer nickel (b) dolomite (c) malachite (d) galena The phenomenon of syneresis is: (a) migration of colloid in an electric field (b) process of converting gel into a true solution (c) separation of the dispersed phase from the gel (d) formation of a sol from a gel Liquid oxygen is (a) pale yellow (b) dark blue (c) pale blue (d) colourless Lucas reagent is: (b) H2SO4 + HCl (a) Na + H2O (d) ZnCl2 + HCl (conc.) (c) MnO2 + H2O

75.

The correct formula of Borax is: (b) Na2[B4O5(OH4).10H2O (a) Na2B4O7.8H2O (c) Na2B4O7.4H2O (d) Na2[B4O5(OH)4].8H2O Toluene on oxidation with chromyl chloride produces: (a) benzaldehyde (b) benzoic acid (c) chlorobenzene (d) none of these Which of the following forms a criterion of purity of organic compounds? (a) Melting and boiling point (b) Solubility (c) Molecular mass (d) Empirical mass B

B

76.

77.

78.

79.

80.

81.

82.

+

H 2 /H HCN CH 3CHO ⎯⎯⎯ → X ⎯⎯⎯→ Y . In the above sequence Y is:

(a) lactic acid (b) acetic acid (c) cinammic acid (d) formic acid The gas that cannot be collected over water is: (b) SO2 (a) N2 (c) O2 (d) PH3 The best absorbed for CO2 is: (a) NaOH (b) NaO (c) H2SO4 (d) water Cinnabar is an ore of: (a) mercury (b) silver (c) zinc (d) lead Which of the following has asymmetric carbon atom? (a)

H H | | H − C − C − Cl | | H H

H H | | (c) H − C − C − CH3 | | H OH

83.

(b)

Cl Br | | H−C−C−H | | H H

H Cl | | (d) H−C−C−D | | H H

R R\ | CO + HCN → R − C − OH is an example of: Reaction, / | R CN (a) nucleophilic addition (c) electrophilic substitution

(b) electrophilic addition (d) nucleophilic substitution

84.

85.

86.

87.

88.

89.

90.

Boiling points of carboxylic acids are: (a) higher than corresponding alcohols (b) lower than corresponding alcohols (c) equal to that of corresponding alcohols (d) none of the above PF3 molecule is: (a) trigonal bipyramidal (b) tetrahedral (c) trigonal pyramidal (d) square planar Oxidation number of +1 for phosphorus is found in: (b) H3PO2 (a) H4P2O7 (c) H3PO4 (d) H3PO3 Commercial detergents contain mainly: (b) RONa (a) ROSO3Na (c) RCOONa (d) ROCH2CHORCH2OR For the reaction, 4A + B → 2C + 2D, the statement which is not correct, is: (a) the rate of formation of D is half the rate of consumption of A (b) the rates of formation of C and D are equal (c) the rate of disappearance of B is one fourth the rate of disappearance of A (d) the rate of disappearance of C is half the rate of disappearance of B Colloidal solutions are not purified by: (a) ultrafilteration (b) electrophoresis (c) electrodialysis (d) dialysis For the process, CO2(s) → CO2(g) (a) both ΔH and ΔS are +ve

91.

(c) ΔH is –ve and ΔS is +ve (d) both ΔH and ΔS are –ve The positron has a charge equal to that of: (a) a proton (c) a neutron

92.

93.

94.

(b) ΔH is +ve and ΔS is –ve

(b) an α-particle (d) an electron

Oxidation number of Mn during the reaction MnO −4 → Mn 2+ changes by: (a) 5 (b) 2 (c) 7 (d) 0 Butter is an emulsion of: (a) fat in water (b) water in fat (c) fat in solid (d) none of these When molecule of acetaldehyde condenses with another dissimilar molecule in the presence of dilute alkali, the reaction is called:

95.

96.

(a) Aldol condensation (b) Benzoin condensation (c) Cross-aldol condensation (d) Perkin’s condensation A compound that gives a positive iodoform test is: (a) pentanal (b) 3-pentanone (c) 2-pentanone (d) 1-pentanol A compound that gives a positive iodoform test is: (a) pentanal (b) 3-pentanone (c) 2-pentanone (d) 1-pentanol

NH 2OH H 2SO4 ⎯⎯⎯⎯ → A ⎯⎯⎯→ B

97.

98.

99.

100.

101.

102.

the product is: (a) perolone (b) nylon-6 (c) caprolactum (d) lactone Lysol is a solution of cresol in: (a) acid (b) heavy water (c) soapy water (d) simple water Which is bad conductor of electricity? (a) HCl (b) HBr (c) HI (d) H2F2 Glucose and fructose are: (a) optical isomers (b) functional isomers (c) position isomers (d) chain isomers 8 drops of Hg are combined to form a bigger single drop. The capacitance of a single small drop and of the single big drop will be in the ratio of: (a) 1 : 2 (b) 1 : 8 (c) 8 : 1 (d) none of these The fundamental frequency of a sonometer wire is n. If the tension is made 3 times and length and diameter are also increased 3 times, then new frequency will be (a) 3n

n

3 3

n (d) 3n 3 A force acting on a conductor of length 5m carrying a current of 8 A kept perpendicular to the magnetic field of 1.5 T is: (a) 100 N (b) 60 N

(c)

103.

(b)

104.

105.

106.

(c) 50 N (d) 75 N The number of beats heard by the driver of a car which is approaching a wall at a speed of 30 km/h and emitting a sound of frequency 300 Hz is : (velocity of sound is 330 m/s) (a) 35 (b) 10 (c) 15 (d) 5 The velocity of sound in open ended tube is 330 m/s, the frequency of wave is 1.1 kHz and length of tube is 30 cm, then number of harmonic it will emit: (a) 2 (b) 3 (c) 4 (d) 5 β-particle is emitted from the nucleus of mass number A with velocity v, then the recoil speed of nucleus will be: M ev 4v (a) (b) A − Me A+ 4 (d)

(c) v 107.

108.

109.

4v ( A − 4)

During nuclear disintegration, which of the following is true? (a) Momentum is conserved (b) Energy is conserved (c) Kinetic energy is conserved (d) None of the above If both spring constants k1 and k2 are increased to 4k1 and 4k2 respectively, then new frequency in term of original frequency f:

(a) f (b) 2f (d) 4f (c) f/2 If two balls are projected at an angle of 60o and 45o and the total height reached are same, then their initial velocities are in the ratio of: (a)

3: 2

(c) 3 : 2

(b)

2: 3

(d) 2 : 3

110.

A pendulum of length 2m lift at P. When it reaches Q, it losses 10% of its total energy due to air resistance. The velocity at Q is (a) 6 m/s (b) 1 m/s (c) 2 m/s (d) 8 m/s

111.

The phase difference between two waves, represented by y1 = 10–6 sin[100t + (x/50) + 0.5]m y2 = 10–6 cos[100t + (x/50)] m where x is expressed in metres and t is expressed in seconds, is approximately: (a) 1.07 rad (b) 2.07 rad (c) 0.5 rad (d) 1.5 rad

112.

The count of α-particle decreases from 28800 to 1800 in 48 h. The half-life of this radioactive element will be: (a) 4 h (b) 8 h (c) 12 h (d) 16 h Two lenses of power 13 D and 2D are placed together. The combined focal length will be: (a) 1 cm (b) 10 cm (c) 100 cm (d) 1000 cm

113.

114.

115.

116.

X-rays of λ = 1Å have frequency: (b) 3 × 1018 Hz (a) 3 × 108 Hz (d) 3 × 1015 Hz (c) 3 × 1010 Hz When 4 equal resistors are connected in series with a battery and dissipate a power of 10 W, what will be the power dissipated through any of them if it is individually connected across the same battery? (a) 40 W (b) 10/3 W (c) 90 W (d) 10 W What is the equivalent capacitance of the arrangement given in figure, A is area?

(a)

Aε 0 ( K1 + K 2 ) 2 2

(b) Aε 0

( K1 + K 2 ) 2d

(c) 117.

118.

119.

121.

122.

(d)

Aε0 ⎛ K1K 2 ⎞ ⎜ ⎟ d ⎝ K1 + K 2 ⎠

If a Carnot engine is working with source temperature 227oC and sink temperature 27oC, its efficiency will be: (a) 40% (b) 10% (c) 67% (d) 50% One proton beam enters a magnetic field of 10–4 Wb/m2 normally. If specific charge is 1011 C/kg and velocity of proton is 109 m/s, then the radius of circle described will be: (a) 0.1 m (b) 10 m (c) 100 m (d) none of these Which one of the following graphs represents uniform motion?

(a)

120.

Aε0 ⎛ K1 K 2 ⎞ ⎟ ⎜ 2d ⎝ K1 + K 2 ⎠

(b)

(c) (d) A body of mass m1 is moving with velocity u. It collides with another stationary body of mass m2. They get embedded. At the point of collision, the velocity of the system: (a) increases (b) decreases but does not become zero (c) remains same (d) zero One projectile moving with velocity v in space get burst into 2 parts of masses in the ratio of 1 : 2. The smaller part becomes stationary, velocity of other part is: 3v (b) (a) uv 2 4v 2v (c) (d) 3 3 Which one is reverse-biased? (a)

(b)

(c) 123.

124.

125.

(d)

If a substance goes in a magnetic field and is pushed out of it. What is it? (a) Paramagnetic (b) Ferromagnetic (c) Diamagnetic (d) Anti-ferromagnetic In solids interatomic forces are: (a) totally repulsive (b) totally attractive (c) both (a) and (b) (d) none of these What should be the minimum velocity at the lowest point of a body tied to a string, so that the string just does not become slack? (a)

Rg

⎛R⎞ (c) ⎜ ⎟ ⎝g⎠

126.

127.

129.

130.

5 Rg

(d)

2 Rg

3/2

Planetary motion in the solar system describes: (a) conservation of kinetic energy (b) conservation of linear momentum (c) conservation of angular momentum (d) none of the above A body of weight mg is hanging on a string which extends in length by l. The work done in extending the string is: mgl 2 (c) 2mgl (d) none of these If wavelength of light in air is 2400 × 10–10 m then what will the wavelength of light in glass (n = 1.5)? (a) 1600Å (b) 7200Å (c) 1080Å (d) none of these The ratio of secondary to primary turns is 4 : 5. If power input is P, what will be the ratio of the power output to power input? (a) 4 : 9 (b) 9 : 4 (c) 5 : 4 (d) 1 : 1

(a) mgl

128.

(b)

(b)

If a transparent slab of refractive index μ = 1.5 and thickness t = 2.5 × 10–5 m is inserted in front of one of the slits of Young’s double slit experiment, how much will be the shift in the interference pattern? The distance between the slit is 0.5 mm and that between slit and screen is 100 cm: (a) 5 cm (b) 2.5 cm

131.

(c) 0.25 cm (d) 0.1 cm If a person standing on a rotating disc stretches out his hands, the speed will: (a) increase (b) decrease (c) remain same (d) none of these

132.

The magnetic flux associated with a closed loop is φ = 6t2 + 7t + 1, where φ is in milliweber and t in seconds. What will be the value of induced emf after 2 second? (a) 29 mV (b) 60 mV (c) 31 mV (d) 22 mV

133.

The work done in carrying a charge of 50μC from a point A to a point B in an electric field is 10 mJ. The potential difference (VB – VA) is: (a) –200 V (b) + 200V (c) –2kV (d) +2kV Threshold wavelength for sodium is 5 × 10–7 m. Photoelectric emission occurs for light of: (a) any wavelength (b) wavelength above 6 × 10–7 m (c) wavelength below 5 × 10–7 m (d) all frequency below 5 × 1014 Hz Two samples A and B of a gas initially at the same temperature are compressed from volume V to V/2. (A isothermally and B adiabatically). The final pressure of A is (a) twice the final pressure of B (b) less than the final pressure of B (c) equal to the final pressure of B (d) greater than the final pressure of B The respective speeds of the molecules are 1, 2, 3, 4 and 5 km/sec. The ratio of their rms velocity and the average velocity will be: (a) 1 : 3 (b) 3 : 4

134.

135.

136.

(c) 3 : 11 137.

(d) 11 : 3

What is the weight of a body at a distance 2r from the centre of the earth, if the gravitational potential energy of the body at a distance r from the centre of the earth is U? U U (a) (b) 2r 3r U (c) (d) Ur 4r

138.

139.

140.

141.

142.

143.

144.

145.

If 100 mH coil carries a current of 1 ampere. Energy stored in its magnetic field is: (a) 1 J (b) 0.5 J (c) 0.1 J (d) 0.05 J 1 of the coil resistance is applied to a moving coil galvanometer, 10 the part of main current passes through the galvanometer:

If a shunt of

(a) 10 I 1 (c) I 10 In a circuit, the value of alternating 10 A. Its peak value will be: (a) 7.07 A (c) 20 A

(b) 11 I 1 (d) I 11 current is measured by hot wire ammeter as (b) 14.14 A (d) 10 A

A polyatomic gas (γ = 4/3) at pressure P is compressed to (1/8)th of its initial volume adiabatically. The pressure will change to: (a) 32 P (b) 16 P (c) 8 P (d) 4 P In a satellite, if the time period of revolution is T, then kinetic energy will be proportional to: 1 (a) 3 (b) T–2/3 T 1 1 (c) (d) 2 T T When the current in a coil changes from 2A to 4A in 0.05 sec, an emf of 8 volts is induced in the coil, the coefficient of self-induction of the coil is: (a) 0.8 H (b) 0.4 H (c) 0.2 H (d) 0.1 H The induced currents always produce expanding magnetic fields round their conductors in a direction that opposes the original magnetic field. This law is called: (a) Lenz’s law (b) Fleming’s law (c) Ohm’s law (d) Kirchhoff’s law A 3 μF capacitor is charged to a potential of 300 V and a 2μF capacitor is charged to 200V. The capacitors are then connected in parallel with plates of opposite polarity joined together. What amount of charge will flow when the plate are so connected? (a) 1300 μC

(b) 700 μC

(c) 250 μC

(d) 600 μC

146.

147.

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150.

The radioactive reaction is 92U238 to 90Th234. The number of α-particles emitted are: (a) 1 (b) 6 (c) 8 (d) 10 A body radiates 5W energy at a temperature of 400K. If the temperature is increased to 1200K, then it radiates energy at the rate of: (a) 405 W (b) 410 W (c) 200 W (d) 81 W Photo-electrons are emitted by a metal surface, only when: (a) light is incident at an angle greater than the critical angle (b) wavelength of the incident light exceeds a certain minimum value (c) frequency of the incident light exceeds a certain minimum value (d) metal is initially charged Under the forward biased condition, the width of depletion layer of a p-n junction diode: (a) increases (b) decreases (c) first increases then decreases (d) unchanged 43 46 1 In reaction 20Ca + X = 21Se + 1H , X is: (a) proton (b) neutron (c) α-particle

(d) none of these