Which of the following is a common type of single-phase motor?

A capacitor start motor is indeed a common type of single-phase motor. It is specifically designed to provide a high starting torque by using a capacitor in the circuit. This capacitor supplies an initial phase shift to the current during startup, allowing the motor to start more efficiently and with sufficient torque for applications that may require overcoming higher loads at the start.

Single-phase motors, in general, are widely used in residential and commercial appliances, such as fans, compressors, and other light industrial machinery. The capacitor start motor, in particular, is highly favored for its performance in applications requiring a reliable startup under load, making it suitable for tasks that must start quickly and efficiently.

In contrast, while induction motors and universal motors are types of motors often seen in various settings, they are not classified as single-phase motors in the same way. The three-phase motor is specifically designed for three-phase systems and thus does not apply here, as it operates on a different principle altogether and requires an appropriate three-phase power supply.