Questions

Sum of numbers in the outer circle in before Arc should come in inner circle patterns in the clock wise direction next Arc.

i.e, 9+6 = 15 comes in next arc of inner circle

7+3 = 10 comes in next arc of inner circle

In the same way, 4+2 = 6 comes in place of '?'.

In the given puzzle, the logic behind is

9 = 72 => 9 x 8 = 72

8 = 56 => 8 x 7 = 56

7 = 42 => 7 x 6 = 42

6 = 30 => 6 x 5 = 30

5 = 20 => 5 x 4 = 20

Similarly,

4 = 12 => 4 x 3 = 12

3 = 6 => 3 x 2 = 6

Microwaves are high-frequency signals in the 300 MHz to 300 GHz range. This is in contrast to radio signals, which are typically broadcast in all directions. Radio signals operate in the 3 Hz to 300 MHz range.

Microwave signals are used for both satellite and ground-based communications.