Tiêu đề 05 paper II Physical science.pdf ✅

5. The role of a coupling capacitor (Cc ) in an amplifier is : (A) To introduce the phase shift of 180° (B) To match the impedance with the source (C) To prevent the mixing of dc signal with input or output (D) To control the voltage gain 6. A common emmiter circuit has an input resistance of 0.6 kΩ and output resistance of 51kΩ, if the current gain is 65, the voltage gain will be : (A) 2456 (B) 5525 (C) 6411 (D) 9306 7. The dominant mechanisms for motion of charged carriers in forward and reverse biased silicon p-n junction are : (A) Drift in forward biased and diffusion in reverse biased (B) Diffusion in forward biased and drift in reverse biased (C) Diffusion in both forward and reverse biased (D) Drift in both forward and reverse biased 8. The output for the following logic circuit with the given inputs is : (A) Y1=0 ; Y2=0 (B) Y1=0 ; Y2=1 (C) Y1=1 ; Y2=0 (D) Y1=1 ; Y2=1 PHYSICAL SCIENCES PAPER – II Note: This paper contains fifty (50) objective type questions, each question carrying two (2) marks. Attempt all the questions. All symbols have their usual meanings. 1. An increase in temperature of a semiconductor will : (A) Increase the number of free electrons (B) Increase the number of valence electrons (C) Increase its electrical resistivity (D) Decrease the number of holes in the valence band 2. The ripple counter is : (A) A ring counter (B) A synchronous counter (C) An asynchronous counter (D) AT Johnson counter 3. Consider the following voltage regulator circuit having zener diode with zener break down voltage (VZ) of 20 V. The minimum value of Vi needed for regulated output is : (Diagram) (A) 45 V (B) 25 V (C) 20 V (D) 14 V 4. The electronic device that possesses a negative resistance region is : (A) FET (B) MOSFET (C) UJT (D) BJT CLA-48865 2 Paper-II ( )
13. If f (x) =    − ≥ < x 3, for x 3 0, for x 3 then, the Laplace transform of f(x) is : (A) s-2e3s (B) s2 e-3s (C) s-2 (D) s-2e-3s 14. If L(x) is a linear differential operator and y1 (x), y2 (x) are two arbitrary functions. Then : (A) L(x)(y1 + y2 ) = Ly1 + Ly2 (B) L(x)(y1 + y2 ) = y1 Ly2 + y2 Ly1 (C) L(x)(y1 y2 ) = Ly1 + Ly2 (D) L(x)(y1 – y2 ) = Ly1 + Ly2 15. The number of independent real parameters of a most general hermitian matrix of order 4 is : (A) 4 (B) 8 (C) 16 (D) 32 16. A conducting cavity is driven as an electromagnetic resonator. If perfect conductivity is assumed, the transverse and normal field components must obey the conditions at the inner cavity wall as : (A) En =0, Bn =0 (B) En =0, Bt =0 (C) Et =0, Bt =0 (D) Et =0, Bn =0 17. A charge q sits at the back corner of a cube. The flux of electric field through the shaded region is : (A) 0 q / ∈ (B) 0 (C) 24 0 q / ∈ (D) 12 0 q / ∈ 9. If A and B are two n×n matrices, then (A+B)2 is : (A) A2 +B2 (B) A2 +B2 +2AB (C) A2 +B2 +AB+BA (D) A2 –B2 10. A is a matrix mentioned below :       − = θ θ θ θ sin cos cos sin A The eigen values of the matrix A are : (A) e±iθ (B) e±2iθ (C) e±3iθ (D) e±iθ/2 11. If S is the closed surface enclosing a volume V, nˆ is the unit normal vector to the surface and r r is the positive vector, then the value of the intergal s ∫ ∫ nˆds is : (A) V (B) 2V (C) Zero (D) 3V 12. Consider a vector k ˆ j 2 ˆ i 3 ˆ p = 2 + + r in the coordinate system ( k)ˆ j, ˆ i,ˆ . The axes are rotated anti-clockwise about the Y-axis by an angle 30°. The vector p r in the rotated coordinate system ( k ) ˆ j , ˆ i , ˆ′ ′ ′ is : (A) ( − )i′ + j′ + ( + )k′ˆ 3 1 ˆ 3 ˆ 1 3 (B) ( + )i′ + j′ + ( − )k′ˆ 1 3 ˆ 3 ˆ 1 3 (C) ( − )i′ + ( + ) j′ + k′ˆ 1 3 ˆ 3 3 ˆ 2 (D) ( − )i′ + ( − ) j′ + k′ˆ 1 3 ˆ 3 3 ˆ 2 CLA-48865 3 Paper-II ( )