1.

Pa(Pascal) is the unit for  

2.

Sound waves in air are  

3.

Materials for rain-proof coats and tents owe their water-proof properties to

4.

RADAR is used for  

5.

 The velocity of sound in air (under normal conditions) is–

6.

 Power of sunglass is- 

7.

At room temperature, which element conducts electricity better than any other element?