cameroon gce intermediate level 2025 electrical machines 1

 

---

 

Questions and Options

 

1. A conductor carries a current of 8A at right angles to a magnetic field having a flux density of 0.5T. The force on the conductor per meter length is:

• A. 400N
• B. 4N
• C. 0.4N
• D. 40N

2. The force exerted on a conductor carrying current placed in a magnetic field is:

• A. Blv
• B. BlI
• C. Blcos$\theta$
• D. BlIcos$\theta$

3. A current of 5A flowing through a coil of 300turns has a magnetomotive force of:

• A. 150A
• B. 1500A
• C. 1500At
• D. 150At

4. In the diagram of figure 1, there is:

• A. self attraction between two magnets
• B. self repulsion between two magnets
• C. repulsion between two magnets
• D. attraction between two magnets

5. The difference between an electromagnet and a permanent magnet is that:

• A. Their magnetic strengths are the same
• B. An electromagnet loses its strength when current is off while a permanent magnet does not
• C. a permanent magnet and an electromagnet cannot be used in the same circuit
• D. electromagnet is heavier in weight than a permanents magnet

6. In a double wound transformer, energy is transferred from the primary to the secondary through:

• A. Mutual inductance
• B. Electrical connection
• C. Electronic connection
• D. Self induction

7. A 480/120V, 2KVA single phase transformer has a primary full load current of:

• A. 4.17A
• B. 5.17A
• C. 15.17A
• D. 17.17A

8. Motor enclosures depend on:

• A. the manufacturer of the motor
• B. the size of the motor and area of application
• C. the way the motor is wound
• D. the supply voltage

9. A key in an electric motor shaft is used to

• A. Cause the shaft not to rotate freely
• B. Guide the shaft and the mechanical load during rotation
• C. Block the shaft when the motor is off
• D. Cause the motor shaft to stop easily when the supply is off

10. The role of an eye bolt in a heavy duty machine is to facilitate the:

• A. locking of the motor
• B. coupling of the stator to rotor
• C. coupling of the motor
• D. lifting from one place to another

11. One disadvantage of the rheostat represented in the diagram of figure 2 is that:

• A. There are many values of resistance in the circuit
• B. There is a sudden cut-off of supply when passing from one resistance value to another
• C. They are connected in parallel to each other
• D. At zero value of resistance the circuit is ON