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According to Bode stability criterian, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is

According to Bode stability criterian, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is Correct Answer 180°

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A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency. This is __________ criterion.
The network formed by resistors and capacitors for modifying the rate of change of gain and the phase shift is called a compensating network. Which of the following statements are not correct ? (A) The main purpose of a compensating network is to modify the performance of op-amp ciruit over the desired frequency range (B) There are two types of op-amps : internally compensated and externally compensated (C) 741 C is an externally compensated op-amp while 709 C is internally compensated op-amp (D) The phase lag and phase lead are most commonly used compensating networks in op-amps (E) Phase lag contributes a positive phase angle and phase lead a negative phase angle Choose the most appropriate answer from the options given below : 
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‘Grand Slam’ refers to winning certain major tennis tournaments in a single calendar year. The name of the tournaments are A. Australian Open, French Open and US Open B. Australian Open, French Open, Wimbledon and US Open.  C. French Open, US Open and Wimbledon D. French Open, US Open, Wimbledon and Olympic
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Five theatres PVR, DT, Chanakya, Regal and Maratha Mandir screen two out of ten films based on Romance, Thriller, Horror, Adventure, Children, Drama, Documentary, History, Religion and Cartoon. Each theatre exhibits only two films and allots two different slots for them, wherein slot I is before slot II. Chanakya screens a Horror film in the first slot, while Maratha Mandir exhibits a Historical film in the second slot. DT exhibits a thriller film in the second slot and Regal exhibits a documentary film. Drama must be exhibited only in the second slot. The children’s film and the Cartoon film are exhibited in the same theatre while the religious film is not in the first slot. If Chanakya screens a Religious film in its second slot, then which of the films can be screened by theatre Regal?
Consider the following statements related to stability of the control system : 1. Poles in right half-plane (rhp) yield pure exponential decaying natural response. 2. If poles of multiplicity greater than one are present on the imaginary axis, then the system is marginally stable, 3. If one pole is present in right-half plane, the system is unstable. 4. A system is stable if the natural response approaches zero as time approaches  infinity. Which of the above statements is/are not correct ?  
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A minimum phase unity feedback system has a bode plot with a constant slope of -20dB/decade for all frequencies. What is the value of the maximum phase margins of the system?