Among the following materials sound travels fastest in
steel
air
vacuum
water
A.
steel
Which phenomenon do bats or dolphins use to find prey, predators or obstacles?
Refraction of sound
Formation of beats
Scattering of sound
Echo location
What did the first electronic digital computer contain?
Transistors
Valves
Core memory
Semiconductor memory
Microsoft Office's personal information manager is
Outlook
Internet Explorer
Organizer
Access
Hard steel contains
2 to 5 per cent carbon
0.5 to 1.5 per cent carbon
0.1 to 0.4 per cent carbon
0.01 to 0.04 per cent carbon
Cement is formed by strongly heating a mixture of
limestone and graphite
limestone and clay
chalk and graphite
clay and graphite