Name the electromagnetic wave which is used in the radar system used in aircraft navigation. Give another use of the wave.

Hint: The electromagnet which is having larger wavelength does not deviate or very less deviate, even if there is any object between the radar and aircraft.

Complete step by step solution:
Radar systems are used to find out the correct position of the aircraft taken off or enemy aircraft position to protect the country from attack.
So, we need an electromagnetic wave in such a way that it can give precise position.
So, we use the microwave as an electromagnetic wave because it has larger wavelength $\left( \lambda \right)$ and thus lower frequency $\left( \upsilon \right)$.
Because \[\lambda \propto \frac{1}{\upsilon }\] $ \Leftrightarrow \lambda \uparrow \Rightarrow \upsilon \downarrow $
And the wave which has higher wavelength or lower frequency can be received by radar without any much deviation and position of aircraft could be found out.

Correct answer is microwave. Microwave is also used in the microwave oven, which is used to cook food and also used to disinfect the kitchen items.

Note: The frequency range for microwave is ${10^9}Hz$ to ${10^{12}}Hz$, it is not visible by naked eyes because it is out of visible region. Frequency of visible region is $4 \times {10^{14}}Hz$to $7.5 \times {10^{14}}Hz$ .