Question

The wavelength of the short radiowaves, micro waves, ultraviolet waves are ${\lambda }_1,{\lambda }_2$ and ${\lambda }_3$ respectively. Arrange them in decreasing order.

• A. ${\lambda }_1,{\lambda }_2,{\lambda }_3$
• B. ${\lambda }_1,{\lambda }_3,{\lambda }_2$
• C. ${\lambda }_3,{\lambda }_2,{\lambda }_1$
• D. ${\lambda }_2,{\lambda }_1,{\lambda }_3$

Answer 1

The correct option is A ${\lambda }_1,{\lambda }_2,{\lambda }_3$

We know that
1. Short radio waves
Wavelength range $=1\times {10}^{-1}m$ to $1\times {10}^{4}m$
Frequency range $=3\times {10}^{9}Hz$ to $3\times {10}^{4}Hz$
2. Microwaves
Wavelength range $=1\times {10}^{-3}m$ to $3\times {10}^{-1}m$
Frequency range $=3\times {10}^{11}Hz$ to $1\times {10}^{9}Hz$
3. Ultraviolet waves
Wavelength range $=1\times {10}^{-8}m$ to $4\times {10}^{-8}m$
Frequency range $=3\times {10}^{16}Hz$ to $8\times {10}^{14}Hz$
So, decreasing order is ${\lambda }_1,{\lambda }_2,{\lambda }_3$.