English Medium इयत्ता ९ - CBSE Question Bank Solutions

A sound signal of 128 vibrations per second has a wavelength of 2.7 m. Calculate the speed with which the wave travels.

State whether the following statement is true or false:

The symbol of element cobalt is CO.

Name the element used as a standard for atomic mass scale.

Which particular atom of the above element is used for this purpose ?

A worker lives at a distance of 1.32 km from the factory. If the speed of sound in air be 330 m/s, how much time will the sound of factory siren take to reach the worker?

A worker lives at a distance of 1.32 km from the factory. If the speed of sound in air be 330 m/s, how much time will the sound of factory siren take to reach the worker?

Give two symbols which have been derived from the "English names" of the elements.

Give two symbols which have been derived from the " Latin names" of the elements.

When we put our ear to a railway line, we can hear the sound of an approaching train even when the train is far off but its sound cannot be heard through the air. Why?

Which subatomic particle was discovered by : Chadwick ?

Name the subatomic particle whose relative charge is : 0

Give the names and symbols of five familiar substances which you think are elements.

Name the elements represented by the following symbols :

Hg, Pb, Au, Ag, Sn

Fill in the blank of the following statement :

 If the nucleus of an atom has atomic number 17, mass number 37 and there are 17 electrons outside the nucleus, the number of neutrons in it is __________.

Fill in the blanks with suitable words .

Wave speed in metres per second equals frequency in ............ multiplied by ..................... in ..................

Fill in the blank with suitable word : 

The speed of sound in a solid is ............... than the speed of sound in air. 

Fill in the blank of the following statement :

The subatomic particle not present in a hydrogen atom is ________

If the speed of a wave is 340 m/s and its frequency is 1700 Hz, then λ for this wave in cm will be :

The maximum speed of vibrations which produce audible sound will be in :

The speeds of sound in four different media are given below. Which of the following is the most likely speed in m/s with which the two under water whales in a sea talk to each other when separated by a large distance?