The question asks about the starting torque characteristics of a shaded pole induction motor. Let's understand the relevant concepts and draw a conclusion:

Working Principle of a Shaded Pole Induction Motor

Shaded pole induction motors are a type of single-phase induction motor. They consist of a stator with a salient pole and a shading coil, forming a shaded pole section. When alternating current flows through the stator winding, it induces a magnetic field in the rotor, creating a rotating magnetic field. This initiates the rotor's motion due to the interaction of fields.

Characteristics of Shaded Pole Induction Motors

• Starting Torque: These motors are known for having a low starting torque because the phase shift produced by the shading coil is small, limiting the initial rotational force.
• Efficiency: The efficiency of shaded pole motors is typically low due to increases in resistive losses and the less efficient rotating magnetic field.
• Applications: Due to these characteristics, they are often used in low-power and low-cost applications such as fans, hairdryers, and small appliances.

Analyzing the Options

1. Low starting torque and low efficiency - This option matches the typical characteristics of shaded pole induction motors. As explained, they have both low starting torque and low efficiency.
2. High starting torque and high efficiency - This is incorrect, as shaded pole motors inherently have low starting torque and low efficiency.
3. High starting torque and low efficiency - This is incorrect because the motors also have low starting torque.
4. Low starting torque and high efficiency - This is incorrect, as these motors do not have high efficiency.

Conclusion

The correct answer is that a shaded pole induction motor has low starting torque and low efficiency.