Question based on a textbook side note
Can electromagnetic waves travel in a vacuum, and what does infrared mean?
برقی مقناطیسی موجیں خلا میں چل سکتی ہیں اور انفرا ریڈ کا کیا مطلب ہے؟
Solution & explanation
Yes: they need no material medium. Infrared lies below red in frequency and beyond red in wavelength. Warm objects emit thermal infrared; infrared itself is electromagnetic radiation, not moving hot air.
Independent study material · English-medium textbook p. 35 · Original book ↗