McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 151. |
Analogous quantities of heat flow and temperature in electrical are and |
| A. | potential and current |
| B. | current and potential |
| C. | power and potential |
| D. | current and power |
| Answer» B. current and potential | |
| Explanation: heat flow in the thermal system is analogous to current flow in electrical, and temperature between two points is analogous to potential between two points in electrical. | |
| 152. |
Ratio of net amount of heat received and stored in the body for certain time interval is known as |
| A. | temperature |
| B. | thermal coefficient |
| C. | thermal storage capacity |
| D. | none of the mentioned |
| Answer» C. thermal storage capacity | |
| Explanation: thermal storage capacity denoted by c is the ratio of the net amount of heat received and stored in the body. | |
| 153. |
Heat transfer coefficient of a material with length l is |
| A. | k/l |
| B. | l/k |
| C. | 1/k |
| D. | kl |
| Answer» A. k/l | |
| Explanation: heat transfer coefficient of a material is the ratio of k and l, where k is the thermal conductivity of material and l is the length of the heat transfer path. | |
| 154. |
Resistance temperature detector is |
| A. | a electrical transducer |
| B. | a mechanical transducer |
| C. | a chemical transducer |
| D. | a physical transducer |
| Answer» A. a electrical transducer | |
| Explanation: resistance temperature detector is an electrical transducer. it is used for measuring the variation in temperature. it is also known as a resistance thermometer. | |
| 155. |
Sensing element in the thermometer must provide |
| A. | small change in resistance |
| B. | no change in resistance |
| C. | large change in resistance |
| D. | infinite change in resistance |
| Answer» C. large change in resistance | |
| Explanation: the sensing element in a thermometer must give a large change in the resistance for a given change in the temperature. | |
| 156. |
Resistance thermometer provides the change in electrical resistance. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: a resistance thermometer provides a change in the electrical resistance with respect to a variation in the temperature. basically resistance thermometers work on the principle of change in the electrical resistance with variation in the temperature. | |
| 157. |
If the sensing element is large, then less amount of heat is required. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: when the sensing element in a resistance thermometer is small in size, then less quantity of heat is required to raise the temperature. platinum, nickel and copper are the commonly used metals for measuring temperature. | |
| 158. |
In a temperature sensing element |
| A. | low value of α is required |
| B. | infinite value of α is required |
| C. | α must be zero |
| D. | high value of α is required |
| Answer» D. high value of α is required | |
| Explanation: in order to achieve a large change in the value of resistance for a small change in the value of temperature, high value of α is required. change in resistance is measured through a wheatstone’s bridge. | |
| 159. |
Nickel and its alloys can be used over a temperature range of |
| A. | 100 to 450 k |
| B. | 10 to 50 k |
| C. | 0 to 25 k |
| D. | 5 to 15 k |
| Answer» A. 100 to 450 k | |
| Explanation: temperature sensors constructed using nickel and its alloys can be used in the temperature range of 100 to 450 | |
| 160. |
How can corrosion be prevented in a resistance thermometer? |
| A. | by immersing the setup in oil |
| B. | by enclosing the elements in a glass tube |
| C. | by using guard rings |
| D. | by painting the elements |
| Answer» B. by enclosing the elements in a glass tube | |
| Explanation: corrosion can be eliminated in a resistance thermometer by enclosing the elements in a protective tubular glass made of pyrex, quartz or crystal depending upon the temperature range. | |
| 161. |
What is the maximum permissible error for class I micrometers? |
| A. | 0.002 mm |
| B. | 0.004 mm |
| C. | 0.008 mm |
| D. | 0.016 mm |
| Answer» B. 0.004 mm | |
| 162. |
Which of the following is caused by careless handling? |
| A. | systematic error |
| B. | gross error |
| C. | random error |
| D. | none of the mentioned |
| Answer» B. gross error | |
| 163. |
‘A system will be error free if we remove all systematic error’. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 164. |
Which of the following is not a fundamental quantity? |
| A. | length |
| B. | angle |
| C. | time |
| D. | luminous intensity |
| Answer» B. angle | |
| 165. |
Which standard is fixed and used for industrial laboratories? |
| A. | international standard |
| B. | primary standard |
| C. | secondary standard |
| D. | working standard |
| Answer» C. secondary standard | |
| 166. |
Which of the following error is caused by poor calibration of the instrument? |
| A. | random error |
| B. | gross error |
| C. | systematic error |
| D. | precision error |
| Answer» C. systematic error | |
| 167. |
How systematic errors are eliminated? |
| A. | frequent measurement |
| B. | replacement of instrument |
| C. | finding mean of reading |
| D. | finding variance of reading |
| Answer» B. replacement of instrument | |
| 168. |
Starting position of an object is represented as x=5.1±0.2m and finishing position as y=6.9±0.3m. What will be the displacement and error in displacement? |
| A. | displacement = 1m, error = 0.5m |
| B. | displacement = 2m, error = 0.36m |
| C. | displacement = 1.8m, error = 0.36m |
| D. | displacement = 1.5m, error = 0.4m |
| Answer» C. displacement = 1.8m, error = 0.36m | |
| 169. |
Which of the following is correct for selective assembly? |
| A. | not suitable for industrial purposes |
| B. | cost increases due to automatic gauging |
| C. | wastage is high due to selective selection |
| D. | this method is followed in ball and roller bearing units |
| Answer» D. this method is followed in ball and roller bearing units | |
| 170. |
For checking straightness, straight edge is placed over a surface and these two are viewed against the light. Which of the following option true if colour of light is red? |
| A. | gap between 0.12 to 0.17 mm |
| B. | gap between 0.2 to 0.7 mm |
| C. | gap between 1.7 to 2 mm |
| D. | gap between 0.0012 to 0.0017 mm |
| Answer» D. gap between 0.0012 to 0.0017 mm | |
| 171. |
Which of the following is the best for the examination of surface finish? |
| A. | touch inspection |
| B. | visual inspection |
| C. | scratch inspection |
| D. | microscopic inspection |
| Answer» D. microscopic inspection | |
| 172. |
What is the relationship between Orificemeter diameter and pipe diameter |
| A. | orificemeter diameter is 0.5 times the pipe diameter |
| B. | orificemeter diameter is one third times the pipe diameter |
| C. | orificemeter diameter is one fourth times the pipe diameter |
| D. | orificemeter diameter is equal to the pipe diameter |
| Answer» C. orificemeter diameter is one fourth times the pipe diameter | |
| 173. |
3 TEMPERATURE: BIMETALLIC STRIP, THERMOCOUPLES |
| A. | strain |
| B. | pressure |
| C. | displacement |
| D. | voltage |
| Answer» C. displacement | |
| 174. |
Relation between temperature and resistance of a conductor is |
| A. | rt = rref [1+t] |
| B. | rt = rref [1+α∆t] |
| C. | rt = rref [1-αt] |
| D. | rt = rref [1-t] |
| Answer» B. rt = rref [1+α∆t] | |
| 175. |
Most metallic conductors have a |
| A. | neutral temperature coefficient of resistance |
| B. | negative temperature coefficient of resistance |
| C. | positive temperature coefficient of resistance |
| D. | zero temperature coefficient of resistance |
| Answer» C. positive temperature coefficient of resistance | |
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