Final answer:
Increasing the voltage in an electric motor leads to a faster speed of rotation. The back emf, which opposes the driving emf, increases as the voltage increases, causing the motor to increase its angular velocity.
Step-by-step explanation:
The speed of an electric motor does increase if you increase the voltage. This is because an increase in voltage leads to an increase in the back emf, which is the opposing force to the driving emf. As the back emf approaches the driving emf, the motor increases its angular velocity or speed of rotation.
For example, if a motor is operating on 240 V electricity and has a 180 V back emf at operating speed, increasing the voltage to 300 V will likely result in a higher back emf and a faster speed of rotation.
The relationship between voltage and speed of rotation in an electric motor is influenced by factors such as mechanical load, current, and temperature. It's important to ensure that the motor is not operating at excessively high speeds that may lead to overheating or damage.