1. For a tachometer, if *θ(t)* is the rotor displacement, e(t) is the output voltage and K is the tachometer constant, then the transfer function is defined as

- Ks
^{2} - K/s
- Ks
- K

2. A tachometer is added to a servo-mechanism because

- it is easily adjustable.
- it can adjust damping
- it converts velocity of the shaft to a proportional d.c. voltage.
- it reduces steady-state error.

3. For a tachometer if *θ(t)* is the rotor displacement, e(t) is the output voltage and K_{t} is the tachometer constant, then the transfer function is defined as

- K
_{t}s^{2} - K
_{t}s - K
_{t}/s - K
_{t}

4. The effect of tachometer feedback in a control system is to reduce

- only time constant
- only gain
- damping ratio
- both gain and time constant

5. In a speed control system, output rate feedback is used to

- Limit the speed of motor
- Limit the acceleration of the motor
- Reduce the damping of the system
- Increase the gain margin

6. In position control systems, the device used for providing rate feedback is called

- servomotor
- tachogenerator
- synchro
- potentiometer