Electromagnetic Waves · Physics · Class 12

The given diagram exhibits the relationship between the wavelength of the electromagnetic waves and the energy of photon associated with them. The three points $\mathbf{P}, \mathbf{Q}$ and $\mathbf{R}$ marked on the diagram may correspond respectively to

The electromagnetic waves used to purify water are

$$\vec{E}$$ and $$\vec{B}$$ represent the electric and the magnetic field of an electro- magnetic wave respectively. The direction of propagation of the wave is along

Which one of the following electromagnetic radiation has the least wavelength?

(a) Name the parts of the electromagnetic spectrum which are (i) also known as heat waves' and (ii) absorbed by ozone layer in the atmosphere.

(b) Write briefly one method each, of the production and detection of these radiations.

(a) How are infrared waves produced? Why are these waves referred to as heat waves? Give any two uses of infrared waves.

OR

(b) How are X-rays produced? Give any two uses of these.

Identify the electromagnetic wave whose wavelengths range is from about

(a) $$10^{-12} \mathrm{~m}$$ to about $$10^{-8} \mathrm{~m}$$.

(b) $$10^{-3} \mathrm{~m}$$ to about $$10^{-1} \mathrm{~m}$$.

Write one use of each.