MCQOPTIONS
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MCQOPTIONS
This section includes 312 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 301. |
A DC series motor is best suited for electrical traction because: |
| A. | it develops high starting torque |
| B. | it runs at very high speed |
| C. | it is cheaper in cost |
| D. | it is more rugged in construction like induction motor |
| Answer» B. it runs at very high speed | |
| 302. |
A DC shunt motor is driving a constant torque load. On inserting an additional resistance in the armature circuit, the speed of the motor will: |
| A. | remains unchanged |
| B. | increases |
| C. | decreases |
| D. | be zero |
| Answer» D. be zero | |
| 303. |
An electrical train employing a dc series motor is running at the fixed speed, when a sudden slight drop in the mains voltage occurs. This would result in: |
| A. | drop in the speed and rise in the current |
| B. | rise in the speed and drop in the current |
| C. | rise in the speed and rise in the current |
| D. | drop in speed with current unaltered |
| Answer» B. rise in the speed and drop in the current | |
| 304. |
A thick wire is used in dc series motor field winding than that in dc shunt motor: |
| A. | to create more flux |
| B. | to reduce the resistance |
| C. | to carry large load current |
| D. | both (b) and © |
| Answer» E. | |
| 305. |
When a dc machine is connected to the dc supply main it will produce: |
| A. | emf in opposition to the applied voltage |
| B. | emf in phase with the applied voltage |
| C. | emf decreases with time |
| D. | none of the above |
| Answer» B. emf in phase with the applied voltage | |
| 306. |
The direction of rotation of a dc motor can be determined by: |
| A. | fleming\s right hand rule |
| B. | fleming\s left hand rule |
| C. | lenz\s law |
| D. | ampere\s law |
| Answer» C. lenz\s law | |
| 307. |
The direction of the armature current in a dc motor is: |
| A. | the same as the generated emf |
| B. | opposite to that of generated emf |
| C. | not dependent upon the direction of the armature emf |
| D. | none of the above |
| Answer» C. not dependent upon the direction of the armature emf | |
| 308. |
If the back emf in a dc motor varnishes suddenly, then the motor: |
| A. | run at very high speeds |
| B. | start hunting |
| C. | burn |
| D. | come to stall |
| Answer» D. come to stall | |
| 309. |
The output power of any electrical motor is taken from the: |
| A. | armature |
| B. | field |
| C. | coupling mounted on the shaft |
| D. | motor frame |
| Answer» D. motor frame | |
| 310. |
The direction of rotation of dc shunt motor can be reversed by interchanging: |
| A. | the supply terminals |
| B. | the field terminals |
| C. | the armature terminals only |
| D. | either field or armature terminals |
| Answer» E. | |
| 311. |
The output indicated on the name plate of any motor is always the: |
| A. | gross power |
| B. | power drawn in volt amperes |
| C. | power drawn in watts |
| D. | output power at the shaft |
| Answer» E. | |
| 312. |
With the increase in the speed of a dc motor: |
| A. | both back emf as well as line current increases |
| B. | both back emf and line current falls |
| C. | back emf increases but the line current falls |
| D. | back emf falls and line current increases |
| Answer» D. back emf falls and line current increases | |