1. Which of the following governor is used to drive a gramophone?
a) Watt’s governor
b) Porter governor
c) Pickering governor
d) Hartnell governor
Explanation: A Pickering governor is mostly used for driving gramophone. It consists of three straight leaf springs arranged at equal angular intervals round the spindle. Each spring carries a weight at the centre.
2. The sensitiveness of a governor depends upon the lift of the sleeve.
a) True
b) False
Explanation: In general, the greater the lift of the sleeve corresponding to a given fractional change in speed, the greater is the sensitiveness of the governor.
3. For two governors A and B, the lift of sleeve of governor A is more than that of governor B, for a given fractional change in speed. It indicates that
a) governor A is more sensitive than governor B
b) governor B is more sensitive than governor A
c) both governors A and B are equally sensitive
d) none of the mentioned
Explanation: In general, the greater the lift of the sleeve corresponding to a given fractional change in speed, the greater is the sensitiveness of the governor.
4. The sensitiveness of the governor ____________ as the speed range decreases.
a) remains unaffected
b) decreases
c) increases
d) none of the mentioned
Explanation: For a given lift of the sleeve, the sensitiveness of the governor increases as the speed range decreases.
5. A governor is said to be stable, if the
a) radius of rotation of balls increases as the equilibrium speed decreases
b) radius of rotation of balls decreases as the equilibrium speed decreases
c) radius of rotation of balls increases as the equilibrium speed increases
d) radius of rotation of balls decreases as the equilibrium speed increases
Explanation: A governor is said to be stable when for every speed within the working range there is a definite configuration i.e. there is only one radius of rotation of the governor balls at which the governor is in equilibrium. For a stable governor, if the equilibrium speed increases, the radius of governor balls must also increase.
6. When the radius of rotation of balls ______________ as the equilibrium speed increases, the governor is said to be unstable.
a) remains constant
b) decreases
c) increases
d) none of the mentioned
Explanation: A governor is said to be unstable, if the radius of rotation decreases as the speed increases.
7. In a Hartnell governor, if a spring of greater stiffness is used, then the governor will be
a) less sensitive
b) more sensitive
c) unaffected of sensitivity
d) isochronous
Explanation: In general, the greater the lift of the sleeve corresponding to a given fractional change in speed, the greater is the sensitiveness of the governor.
8. When the speed of the engine fluctuates continuously above and below the mean speed, the governor is said to be
a) stable
b) unstable
c) isochronous
d) hunt
Explanation: The isochronous governor is not of practical use because the sleeve will move to one of its extreme positions immediately the speed deviates from the isochronous speed.
9. For isochronous Hartnell governor
a) mg + S1 / mg + S2 = r1/r2
b) mg – S1 / mg – S2 = r2/r1
c) S1/S2 = r1/r2
d) S2/S1 = r1/r2
Explanation: mg + S1 / mg + S2 = r1/r2
10. Effort of a governor is the
a) mean force exerted at the sleeve for a given percentage change of speed
b) workdone at the sleeve for maximum equilibrium speed
c) mean force exerted at the sleeve for maximum equilibrium speed
d) none of the mentioned
Explanation: The effort of a governor is the mean force exerted at the sleeve for a given percentage change of speed (or lift of the sleeve).