Communication Systems Questions and Answers

Which of the following statements regarding optical sensors is false A An optical fiber can carry light received at a limited range of angles B All optical sensors use optical fibers C The range of a fiber optic spectrophotometer is obtained using multiple gratings D None of the above

83 The following Figure shows a logic gate circuit with two inputs A and B and the output Y The voltage waveforms of A B and Y are given 2011 A B A B 0 1 1 Y 0 Logic gate circuit The logic gate is a NAND gate c OR gate 13 14 b NOR gate d AND gate

33 From a circular disc of radius R a triangular 33 portion is cut see fig The distance of COM of the remaining disc from centre of disc O is 4R 1 3 x 2 3 2R 3 2 450 45 C SR 2 7 2 R 3 1 quien e feel all fa 1 3 4R 3 2 45 2R 3 2

A conical hole is machined in a block of metal whose emissivity is 0 5 The hole is 2 5 cm in diameter at the surface and 7 5 cm deep If the metal block is heated to 800 K calculate the radiation emitted by the hole Calculate the value of an apparent emissivity of the hole defined as the ratio of the actual energy emitted by the hole to that energy which would be emitted by a black surface having an area equal to that of the opening and a temperature equal to that of the inside surfaces

QUESTION A25 1 mark The velocity of an object is expressed as a graph in the figure below Determine the displacement of the object from t 3 s to t 10s v m s a 48 m b 43 8 m c 33 8 m 8 7 8 n 3 2 1 1 2 3 4 5 6 7 8 9 10 11 760 d 39 m e None of the above

7 57 Calculate the rate of flow of glycerine of density 1 25 10 kg m through the conical section of a pipe if the radii of its ends are 0 1 m and 0 04 m and the pressure drop across its length is 10 N m Ans 6 44 10 m s

Percentage error in the determination of g is If velocity of light in vacuum 3 x 108 m s acceleration due to gravity 9 81 m s2 and density of mercury 13600 kgm be adopted as the fundamental units choose the correct option s a unit of mass is 1 05 x 1052 kg b unit of length is 9 17 x 10 5 m

Find the rate of flow of glycerine of density 1 25 10 Kg m through the conical section of a pipe if the radii of its end are 0 1 m and 0 04 m and the pressure drop

A microwave telephone link operating at the central frequency of 10 GHz has been established If 2 of this di is available for microwave communication channel then how many telephone channels can be simultaneously granted if each telephone is alloted a bandwidth of 10 KHz a 2 104 c 5 x 107 b 104 d 6 10 9 10 11

A solid cylinder of mass m length I and area of cross section A is placed as shown in the figure If Young s modulus is Y then strain energy stored in the cylinder is A C 2 m g l 3AY 2 m g 1 7 A V B D m g 1 6AY m g 1 AY

Two particles of masses 2 g and 36 g respectively are attached to two ends of a rigid light rod of length 1 9 m The centre of the mass of the system from 2 g particle is nearly at distance of 1 4 m 1 8 m 1 7 m 0 95 m

Determine the output voltage of a differential amplifier for the input voltage of 300 micro volt and 240 micro volt The differential gain of the amplifier is 5000 and value of CMRR is a 100 b 100000

A signal of frequency 20 kHz and peak voltage of 5 Volt is used to modulate a carrier wave of frequency 1 2 MHz and peak voltage 25 Volts Choose the correct statement A Modulation index 5 side frequency bands are at 1400 kHz and 1000 kHz B Modulation index 5 side frequency bands are at 21 2 kHz and 18 8 kHz C Modulation index 0 8 side frequency bands are D 180 kHz and 1220 kHz Modulation index 0 2 side frequency bands are at 1220 kHz and 1180 kHz

Which among the following statements is correct regarding the dependence of voltage gain of an amplifier on the frequency of the signal A the signal does not depend upon frequency of Your Answer B signal increases with frequency of the decreases with frequency of the signal D with frequency of the signal initially constant and then decreases

The figure shows a digital circuit constructed using negative edge triggered J K flip flops Assume a starting state of Q2Q Q0 000 This state will repeat after how many number of the cycles of the CLK 1 Jo Qo Clock clock 1 Ko Qo J clock 1 K Q1 Q J clock 1 K Q2 Q

Let x t be a periodic signal with time period T Let y t x t to x t to for some to The Fourier Series coefficients of y t are denoted by bk If bk 0 for all odd k then to can be equal to 1 2 3 4 T 8 T 4 T 2 2T