Which of the following electromagnetic waves has the lowest frequency?

Which of the following is responsible for the greenhouse effect?

$A$ monochromatic source of light operating at $15 \text{ kW}$ emits $2.5 \times 10^{22} \text{ photons/s}$. The region of an electromagnetic spectrum to which the emitted electromagnetic radiation belongs to . . . . . . . (Take $h = 6.6 \times 10^{-34} \text{ J}\cdot\text{s}$ and $c = 3 \times 10^8 \text{ m/s}$).

What is the approximate wavelength range of the electromagnetic spectrum?

What is the frequency range of $AM$ radio waves?

Which of the following rays has the maximum frequency?