Q.1. Select the best option/answer and fill in the appropriate box on the Answer Sheet.

(i) If A= 6i-8j, then 4A has the magnitude:

(a) 40
(b) 10
(c) 20
(d) None of these

(ii) Let A= 2i+6j-3k and B= 4i+2j+k then A.B equals:
(a) 8i+12j-3k
(b) 17
(c) 23
(d) None of these

(iii) If V is an operator, then V.V means:
(a) Gradient of a Scalar field
(b) Curl of a vector field
(c) Divergence of a Vector field [B]
(d) None of these (its Laplacian)

(iv) The volume of a parallelepiped bounded by Vectors A,B and C can be obtained from the expression:
(a) ( A x B ).C
(b) (A.B)x C
(c) ( A x B ) x C
(d) None of these

(v) A force acting on a particle is conservative if:
(a) It obeys Newton's third law
(b) It obeys Newton's second law
(c) It works equals the change in Kinetic energy
(d) None of these (work done in a closed loop = 0 ie. independant of the path)


(vi) A torque applied to a rigid object always tends to produce:
(a) A rotational acceleration
(b) A linear acceleration
(c) Precision
(d) None of these

(vii) When the velocity of a body is constant, its acceleration is:
(a) Maximum
(b) Zero
(c) Infinity
(d) None of these

(viii) In the absence of external torque the total angular momentum is:
(a) Constant
(b) Zero
(c) infinity
(d) None of these

(ix) The rate of change of Momentum of the particle is:
(a) Energy
(b) Force
(c) Impulse
(d) None of these

(x) Constructive and destructive superposition of waves is observed in:
(a) Polarisation
(b) Interference
(c) Diffraction
(d) None of these

(xi) The intensity of a wave is proportional to the square of:
(a) Amplitude
(b) Time
(c) Intensity
(d) None of these

(xii) The colours in soap bubbles, oil slick etc. in a thin film is due to:
(a) Diffraction
(b) Polaristaion
(c) Interference
(d) None of these

(xiii) For higher resolution, in a diffraction grating, one needs to have:
(a) Large number of ruling
(b) Small number of ruling
(c) No rulings at all
(d) None of these

(xiv) To produce interference, the sources must be:
(a) Intense
(b) Incoherent
(c) Coherent
(d) None of these


(xv) Interference fringes are of:
(a) Unequal width
(b) Equal width
(c) Variable width
(d) None of these

(xvi) A Carnot Cycle is:
(a) a rectangle on a P-V graph
(b) bounded by two isotherms and two adiabatics
(c) any four sided process on a P-V graph
(d) None of these


(xvii) In an Adiabatic process:
(a) The temperature of the system remains constant
(b) The temperature of the system must change ( doubt)
(c) The internal energy of the system remains constant
(d) None of these

(xviii) A Carnot Cycle heat engine operates between 227°C and 127° C. Its efficiency is:
(a) 44%
(b) 20%
(c) 79%
(d) None of these

(xix) Metals pipe carrying water some times bursts in winter because:
(a) Water expands (when it cools on becoming ice ) ( doubt)
(b) Ice expands when melts
(c) Metal contracts more than water
(d) None of these

(xx) A Fahrenheit thermometer and Celsius thermometer shows the same reading at:
(a) 200°
(b) -40°
(c) 100°
(d) None of these