This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Movement of Piston in Dash Pot”.
1. The dashpot timer is_______
d) Free Movement
Explanation: The dashpot timer is an automatic timer. It is used in several machines and has ‘n’ number of variations. It is used in many applications such as printing presses, generating motors and in many irrigation systems.
2. Mechanical timers measure time using______
a) Thermal Mechanism
b) Computer code
Explanation: Mechanical timers use clock to measure time intervals. It can be categorised into two types. One of them is a stop watch, which measures the elapsed time and the other is an hourglass. Both these methods follow the same principle of recording the time intervals.
3. Which among the following is an oldest mechanical timer?
a) Stop watch
c) Balance wheel
d) Hour glass
Explanation: Hour glass is a device that is used to measure the passage of time. An hour glass contains two glass bulbs connected by a narrow neck. This allows a trickle of material from the upper bulb to the lower one. (Material most commonly used: sand).
4. Electronic timers are essentially ________
a) Quartz clock
b) Stop watch
c) Hour glass
Explanation: Electronic timers are quartz clocks. They are modified with special electronics. They can achieve higher precision when compared to mechanical timers. Electronic timers work on digital electronics which have analog or digital display.
5. Software timers work on__________
a) Quartz glass
b) Balance wheel
c) Computer code
Explanation: Software timers are not devices or parts of devices. They work on computer code which relies on the accuracy of a clock generator. It is usually built into a hardware device that runs on the principle of software.
6. What type of device is a dashpot?
Explanation: A dashpot contains a damper which resists the motion with the help of a viscous flow. The force so produced is directly proportional to the velocity. But, it acts in the opposite direction, thus slowing the motion and absorbing the energy. By this way, the dashpot works on a mechanical basis.
7. What are the types of dashpot?
a) Linear and rotary
b) Reciprocating and nonuniform.
c) Linear and reciprocating
d) Circular and rotational
Explanation: Dashpot is divided into two types, linear and rotary types. Linear dashpots are specified by the amount of linear displacement (stroke) and force per velocity (damping coefficient). Rotary dashpots will have force per velocity( damping coefficient) in torque so developed.
8. Which among the following is not an application of the dashpot?
a) Door closer
b) Consumer electronics
d) Pilot Static Tube
Explanation: Pilot static tube is a system that uses an automatic control scheme to detect pressure. It has several holes connected to one side of the device. These outside holes are called as a pressure transducer, which controls the automatic scheme during fluid flow.
9. Example of amorphous substance is _______
Explanation: Amorphous substances are substances that have an internal structure. These internal structures are made up of interconnected structural blocks. They have a long-range order. A good example of an amorphous substance is a polymer.
10. Which among the following is not a type of crystalline substances?
d) Hydrogen bond
Explanation: A crystalline substance does not undergo hydrogen bonding. A crystalline substance is a substance in which the constituents are arranged in a highly ordered microscopic structure. It forms a crystal lattice in all directions.
11. Fluid sealing in a dashpot is achieved using________
b) Piston rings
Explanation: Fluid sealing in a dashpot is achieved using a piston ring. Piston rings are a number of narrow iron rings which are fitted loosely into the grooves of the piston. The rings split at a point on the rim which is placed just below the crown.
12. Which among the following is the best suitable material for making a piston?
Explanation: Pistons are made from aluminium alloys. The properties of these alloys can be improved by forging technique. Forging is done to improve the fatigue life and strength of the piston.
Sanfoundry Global Education & Learning Series – Fluid Mechanics.
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