Which frequency of microwave is used by a microwave oven to cook food (in $GHz$)?

If a source of power $4 \ kW$ produces $10^{20}$ photons/second,the radiation belongs to a part of the spectrum called

Match List-$I$ with List-$II$:

List-$I$ (Electromagnetic wave)	List-$II$ (Production)
$A$. Microwave	$I$. Electrons in atoms emit light when they move from a higher energy level to a lower energy level
$B$. Visible light	$II$. Radioactive decay of nucleus
$C$. Gamma rays	$III$. Vibration of atoms and molecules
$D$. Infra-red rays	$IV$. Klystron valve or magnetron valve

Choose the correct answer from the options given below:

Which of the following waves has the maximum wavelength?

In the following,List $A$ consists of the wavelength range of different $EM$ waves and List $B$ consists of ways to produce them. Match the following lists.
| List $A$ | List $B$ |
| :--- | :--- |
| $A$. $400 \ nm$ to $1 \ nm$ | $1$. Radioactive decay of the nucleus. |
| $B$. $> 0.1 \ nm$ | $2$. Vibration of atoms and molecules. |
| $C$. $1 \ mm$ to $700 \ nm$ | $3$. Rapid acceleration and deceleration of electrons in aerials. |
| $D$. $< 10^{-3} \ nm$ | $4$. Inner shell electrons in atoms moving from one energy level to a lower level. |

Which of the following waves are associated with communication?