Which of the following options increase the sensitivity of a bubble tube?
1. Using a liquid of greater surface tension
2. Increasing the diameter of the tube
3. Increasing the length of the tube
4. Decreasing the diameter of the tube
Select the correct answer using the codes given below:
1
1 and 2 only
2
2 and 3 only
3
3 and 4 only
4
1 and 4 only