English Medium इयत्ता ९ - CBSE Question Bank Solutions

What is the range of frequencies associated with (a) infrasound (b) audible sound, and (c) ultrasound ?

The atomicities of ozone, sulphur, phosphorus and argon are respectively :

Write any three applications (or uses) of ultrasound.

Define the following terms : (a) Echolocation (b) Echocardiography, and (c) Ultrasonography.

Name an animal which navigates and finds food by ecolocation.

Which of the two produces ultrasonic waves : porpoise or whale ?

What is sonar ? Explain its use.

A sonar station picks up a return signal after 3 seconds. How far away is the object ? (Speed of sound in water = 1440 m/s).

The element having atomicity 'four' is most likely to be :

In SONAR we use:

The ultrasound waves can penetrate into matter to a large extent because they have :

What type of waves are generated by SONAR device fixed to a fishing ship ?

Write down the formulae for the following compounds :

Calcium oxide

Write down the formulae for the following compounds :

Magnesium hydroxide

An element Z has a valency of 3. What is the formula of oxide of Z ?

An element Z has a valency of 3. What is the formula of oxide of Z ?

Name the elements water is made of. What are the valencies of these elements ? Work out the chemical
formula for water.

If the valency of hydrogen is 1 and that of nitrogen is 3, work out the formula for ammonia.