Microwaves are commonly used for:

Solution

Physics sir · 2 steps

Match each job to its wavelength: radar needs short waves that pass through air and reflect cleanly.

1. Where microwaves sit. Microwaves lie between radio waves and infrared, with wavelengths from about 1 mm to 30 cm. Their photon energy is far too low to ionise atoms or kill cells.

   Use	Wave actually used	Why
   Radar	Microwaves	Short wavelength gives a narrow beam that reflects off aircraft and returns sharp echoes
   Treating cancer	Gamma rays (or X-rays)	High-energy photons destroy tumour cells
   Sterilizing instruments	Ultraviolet or gamma rays	Energetic enough to kill bacteria
   Bone imaging	X-rays	Pass through soft tissue but are absorbed by bone

2. So. Radar is the microwave job, so the answer is (a). The other three uses need high-energy radiation from the short-wavelength end of the spectrum.

The idea to keep. Low-energy waves (radio, microwave) carry signals and detect objects. High-energy waves (UV, X-ray, gamma) image the body, sterilize or kill cells. Place the wave first, then its uses follow.

Answer from the NTA final answer key. Solution by PrepWiser.