A motor drives a small gear with 10 teeth which is connected to a larger gear with 40 teeth. What is the gear ratio?

1. 4 : 1
2. 1 : 4
3. 1 : 2
4. 2 : 1

Which of the following string operators in Python is used to find the length of a string 'a'?

1. len(a)
2. len()
3. a.len()
4. a.len(a)

In machine learning, testing data is primarily used to:

1. train the model for better performance.
2. measure model performance on unseen data.
3. store training parameters.
4. provide labels for training.

The function of a sensor is to:

1. detect changes in environment and send signals.
2. process the input data and make decisions.
3. change electrical energy into motion.
4. supply power to the robot.