BSc Physics SEM III ATKT PHYSICS PAPER II Question Paper - Mumbai University | munotes

Questions asked in this paper

• (2) Figures to the right indicate maximum marks

1. Q1 <A) Select correct answer. 1 The scale factors of cylindrical co-ordinates (9, are 2 The work done in respective units by the force F yf in moving a particle from origin to point P (2, 2) When a decibel value is computed by comparing a power value to 1 mW it is called 4 The value of stability factor for a base-resistor bias is 5 An ideal op-amp has 12 marks
   • a) infinite input and output resistance
   • b) infinite CMRR and zero temperature drift
   • c) zero input resistance and zero slew rate
   • d)zero output resistance and large offset voltage 6 For sustained sinusoidal oscillations , total loop gain should be
   • B) Answer in one sentence. Give the necessary and sufficient condition that the line integral of A 0 for every close curve C 2 should be an ideal value of input resistance of an amplifier? What is bandwidth of an op-amp? Fill in the Blanks. (5) 1 If the work done by a force in moving a particle in closed path is zero, the force field is said to be 2 Volume element in cylindrical co-ordinate system is 3
2. Q3 Halving the power of an amplifier corresponds to a decrease of -------- dB 4 The operating point is also called the ------- point 5 op-amp integrator circuit will convert a square wave into a -----wave Attempt any one. (8) 1 Check the Fundamental theorem for Gradient using = x* + 4xy + 2yz? and end points and B(1,1,1) considering two paths
   • ii) The parabolic path = x*,y =x 2 Verify Stoke’s theorem for F = (2x yz k taking a surface S, upper half of the sphere x* + y? + z* = 1 and C is its boundary
   • B) Attempt any one. 1 Determine the scale factors for spherical coordinate system 8
   • C) Attempt any one. lif , where V(x, y, z) is a single valued continuous function, show that f F .d? is independent of path 4
   • a) Straight line y = x from (0,0) to (1,1)
   • b) Parabola y = x? from (0,0) to (1,1)
3. Q3 A) Attempt any one. Draw the circuit diagram of CE amplifier using fixed bias method. Derive expression for Ig and Hence obtain the expression for stability factor. Give one advantage and disadvantage of this method 2 Obtain the expression for the input Ri and output Ro resistance of a general amplifier What should be their ideal values? Explain with proper reasoning 8 marks
   • B) Attempt any one. 1 Draw the circuit diagram for voltage divider CE amplifier. Show that the stability factor is unity. Give one advantage and disadvantage of voltage divider bias 2 With the help of a block diagram derive the relation between gain without feedback and gain with feedback when negative feedback is introduced. Explain, What is the effect of negative feedback on bandwidth? 8
   • C) Attempt any one. Inanegative feedback amplifier A = 100, and input signal voltage is 40 mV Determine (i) voltage gain with feedback (ii) Feedback voltage (iii) output voltage 2 What is meant by faithful amplification? Give three conditions to achieve faithful 4
4. Q4 A) Attempt any one 1 Draw the circuit diagram of Colpitt’s oscillator. Explain its working. What is the (8) frequency of oscillation of the circuit? 2 What is a differentiator? Explain its working. Derive the relation between input and
   • B) Attempt any one
5. Q1 What is an oscillator? Draw the circuit diagram of phase shift oscillator. Discuss its 2 What is a non-inverting amplifier? Draw the circuit diagram of non-inverting amplifier using op-amp. Derive the expression for gain of the circuit 8 marks
   • C) Attempt any one 1 Define comparator circuit. Draw the circuit diagram and sketch the 2 A typical op-amp inverting adder circuit has, = V2 = 3V and V3 = 4V. The three input resistors are Ri = 4KQ , Ro = 4KQ and R3 = A resistance of SKQ is used in the feedback path. What will be the output voltage? What should be the value of feedback resistor if the circuit has to work as inverting averager?
6. Q5 Attempt any Four : 1 State and explain the Fundamental theorem for Curl 2 Considering scale factors for cylindrical co-ordinates derive expressions for arc, area and volume elements 3 For the emitter bias circuit shown below, find Tg, Ic,Vc and Vcr for B = 85 and = 4 An amplifier has a signal input voltage Vi, of 0.25 V and draws 1 mA current from the source. The amplifier delivers 8 V load at 10 mA. Determine the voltage gain, current gain and power gain in decibels Co = 0.4uF. Calculate the frequency of oscillation. If a capacitance of 0.4yF is connected parallel to C2, what will be the output frequency? 6 typical op-amp integrator circuit, R = 10KQ and C = 2.2uF and Vi = 50 mV What will be output voltage Ims after input is applied? How much time is required for the output to become -5V? 20 marks

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