The hardest naturally occurring substance on Earth

One Astronomical Unit (AU) is the average distance between-

The momentum of a body depends on:

What is the SI unit for measuring speed?

Which device uses ultrasonic waves for getting images of internal organs of human body?

Why does a solid chunk of iron float in mercury but sink in water?

Smog is a combination of –

What conditions must be met for stationary waves to form?

Which of the following instruments is correctly matched with its function?

I) Voltmeter - Measures potential difference 

What is the audible frequency range?

Twinkling of the Stars is due to the phenomenon of