An example of longitudinal waves (in gas as a medium) is ______.
1). heat waves
2). radio waves
3). electromagnetic waves
4). sound waves
4. Select the related word/letters/numbers from the given alternatives:8: 32 : : ? : 108
5. O is the circumcentre of $\triangle$ABC. If AO = 8 cm, then the length of BO is
7. India's population growth is characterized by
8. Select the related word/letters/number from the given alternatives.VERMIN :? :: ORDERS : ERSORD
10. What is the equation of the line if its slope is $\frac{3}{4}$ and y-intercept is 5?