May, 2022Flame Institute

Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry’s standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a …

At what distance from the centre of the earth, the value of acceleration due to gravity g will be half that on the surface (R = radius of earth)

(a) 2 R (b) R (c) 1.414 R (d) 0.414 R Answer: d (4)

5. Nylon is not a

a. Condensation polymer b. Polyamide c. Copolymer d. Homopolymer Ans. d (6)

4. Polyethylene is

a. Random copolymer b. Homopolymer c. Alternate copolymer d. Crosslinked copolymer Ans. b (13)

3. Which of the following is an example of condensation polymer

a. Nylon b. Bakelite c. Urea-formaldehyde resin d. all of these Ans. d (16)

2. A thermoplastic among the following is

a. Bakelite b. Polystyrene c. Terylene d. Urea-formaldehyde resin e. Nylon Ans. b (11)

1. Correct statement for thermoplastic polymer is

a. It does not become soft on heating under pressure b. it can not be remoulded c. it is either linear or branched chain polymer d. it is cross-linked polymer Ans. c (9)

The acceleration due to gravity near the surface of a planet of radius R and density d is proportional to

(a) d/R2 (b) dR2 (c) dR (d) d/R Answer: c (9)

What will be the acceleration due to gravity at height h if h >> R. Where R is radius of earth and g is acceleration due to gravity on the surface of earth

(a) g/(1 + h/R )2 (b) g ( 1 – 2h/R ) (c) g/( 1- h/R )2 (d) g ( …

Weight of a body is maximum at

(a) Moon (b) Poles of earth (c) Equator of earth (d) Centre of earth Answer: b (5)

A man can jump to a height of 1.5 m on a planet A. What is the height he may be able to jump on another planet whose density and radius are, respectively, one-quarter and one-third that of planet A

(a) 1.5 m (b) 15 m (c) 18 m (d) 28 m Answer: c (4)

A thin wire of length L and uniform linear mass density ρ is bent into a circular loop with centre at O as shown. The moment of inertia of the loop about the axis XX’ is

(a) ρL3/8π2 (b) ρL3/16π2 (c) 5ρL3/16π2 (d) 3ρL3/8π2 Ans. d (8)

63. Two discs of same thickness but of different radii are made of two different materials such that their masses are same. The densities of the materials are in the ratio 1 : 3. The moments of inertia of these discs about the respective axes passing through their centres and perpendicular to their planes will be in the ratio

(a) 1 : 3 (b) 3 : 1 (c) 1 : 9 (d) 9 : 1 Ans. b (44)

The angular speed of earth, so that the object on equator may appear weightless (g = 10 m/s2 , is , radius of earth 6400 km)

(a) 1.25×10-3 rad/sec (b) 1.56 ×10-3 rad/sec (c) 1.25×10-1 rad/sec (d) 1.56 rad/sec Answer: a (4)

68. A thin wire of length l and mass M is bent in the form of a semi-circle. What is its moment of inertia about an axis passing through the ends of the wire

(a) ML2/2 (b) ML2/π2 (c) 2ML2/ π2 (d) 2ML2/2π2 Ans. d (3)

Assume that the acceleration due to gravity on the surface of the moon is 0.2 times the acceleration due to gravity on the surface of the earth. If Re is the maximum range of a projectile on the earth’s surface, what is the maximum range on the surface of the moon for the same velocity of projection

(a) 0.2 Re (b) 2 Re (c) 0.5 Re (d) …

If the mass of earth is 80 times of that of a planet and diameter is double that of planet and ‘g’ on earth is 9.8 m/s2 , then the value of ‘g’ on that planet is

(a) 4.9 m/s2 (b) 0.98 m/s2 (c) 0.49 m/s2 (d) 49 m/s2 Answer: c (6)

R and r are the radii of the earth and moon respectively. pe and pm are the densities of earth and moon respectively. The ratio of the accelerations due to gravity on the surfaces of earth and moon is

(a) R/r pe/ pm (b) r/R pe/ pm (c) r/R pe/ pm (d) R/r pe/ pm Answer: a (6)

66. Two point masses of 0.3 kg and 0.7 kg are fixed at the ends of a rod of length 1.4 m and of negligible mass. The rod is set rotating about an axis perpendicular to its length with a uniform angular speed. The point on the rod through which the axis should pass in order that the work required for rotation of the rod is minimum is located at a distance of

(a) 0.4 m from mass of 0.3 kg (b) 0.98 from mass of 0.3 kg (c) 0.70 m from mass of 0.7 kg (d) 0.98 m from mass of 0.7 kg Ans. b (7)

65. If solid sphere and solid cylinder of same radius and density rotate about their own axis, the moment of inertia will be greater for (L = R)

(a) Solid sphere (b) Solid cylinder (c) Both (d) Equal both Ans. a (45)

Assuming earth to be a sphere of a uniform density, what is the value of gravitational acceleration in a mine 100 km below the earth’s surface (Given R = 6400 km)

(a) 9.66 m/s2 (b) 7.64 m/s2 (c) 5.06m/s2 (d) 3.10 m/s2 Answer: a (5)

The angular velocity of the earth with which it has to rotate so that acceleration due to gravity on 60o latitude becomes zero is (Radius of earth = 6400 km. At the poles g=10 ms-2)

(a) 2.5 × 10-3 rad /s (b) 5.0 × 10-1 rad /s (c) 10 × 101 rad /s (d) 7.8 × 10-2 rad /s Answer: a (5)

62. One quarter sector is cut from a uniform circular disc of radius R. This sector has mass M. It is made to rotate about a line perpendicular to its plane and passing through the centre of the original disc. Its moment of inertia about the axis of rotation is

(a) 1/2 MR2 (b) 1/4 MR2 (c) 1/8 MR2 (d) √2 MR2 Ans. a (6)

61. From a uniform wire, two circular loops are made (i) P of radius r and (ii) Q of radius nr. If the moment of inertia of Q about an axis passing through its centre and perpendicular to its plane is 8 times that of P about a similar axis, the value of n is (diameter of the wire is very much smaller than r or nr)

(a) 8 (b) 6 (c) 4 (d) 2 Ans. d (6)

An object weights 72 N on earth. Its weight at a height of R/2 from earth is

(a) 32 N (b) 56 N (c) 72 N (d) Zero Answer: a (5)

The height of the point vertically above the earth’s surface, at which acceleration due to gravity becomes 1% of its value at the surface is (Radius of the earth = R)

(a) 8 R (b) 9 R (c) 10 R (d) 20 R Answer: b (7)

If the Earth losses its gravity, then for a body

(a) Weight becomes zero, but not the mass (b) Mass becomes zero, but not the weight (c) Both mass and weight become zero (d) Neither mass nor weight become zero Answer: a (7)