A d.c. shunt motor runs at 500 r.p.m. on a 200 V supply. Its armature resistance is 0.5 Q and the current taken is 30 Amp in addition to field current. What resistance must be placed in series with armature to reduce the speed to 300 rpm ? The current in armature remains the same.

SOLVE CAREFULLY!! Please Write Clearly and Box the final Answer Hint : Enter your answer to the 3rd nearest decimal place in seconds.

(b) Figure Q5 (b) shows a state transition diagram consisting of four states with the signals S, W, X, Y and Z using Finite State Machine (FSM) concept. X'I Z so XY'I Z X+Y/ W Y/ W X/ W S3 S1 X'Y'/ W Y'IZ Y'IZ S2 XYI Z Figure Q5 (b) Based on the Figure Q5 (b), answer the following questions: (1) What is the types of FSM model shown in Figure Q5 (b) ? (ii) Determine the input signals. (iii) Determine the output signals?

As we know that opamps working on a dual power supply and both power supply should be in the same polarity. If the power supply is not similar in both the polarity the dc output will drift to either side depending on the higher amplitude of polarity and sometimes the case is like this offset nulling will become difficult to achieve So what is "offset nulling" ? Please explain