One of the vibrations of the string makes

As compare to air, sound travels faster in

A. liquids

B. gases

C. vacuum

D. fluids

Sounds of vehicles, aircrafts and machines are called

A. artificial sounds

B. natural sounds

C. noise

D. normal sounds

Large empty room often sounds

A. full

B. hollow

C. noisy

D. repeating

For communication astronauts use radio because

A. sound travels at very high speed in vacuum

B. sound does not travel in vacuum

C. vacuum repels sounds

D. sound energy turns into light in vacuum

In concert halls, soft materials and carpets are used to

A. increase sound waves

B. absorb sound waves

C. retract sound waves

D. refract sound waves