Which of the following is the infrared ray wavelength?
A.
$${10^{ - 4}}cm$$
B.
$${10^{ - 5}}cm$$
C.
$${10^{ - 6}}cm$$
D.
$${10^{ - 7}}cm$$
Answer :
$${10^{ - 4}}cm$$
Solution :
The wavelength of infrared region is $$8 \times {10^{ - 5}}cm$$ to $$3 \times {10^{ - 3}}cm.$$ So maximum wavelength of infrared region
$$\eqalign{
& = 8 \times {10^{ - 5}}cm \cr
& \approx {10^{ - 4}}cm. \cr} $$
Releted MCQ Question on Electrostatics and Magnetism >> Electromagnetic Waves
Releted Question 1
Out of the following options which one can be used to produce a propagating electromagnetic wave?
The electric field associated with an electromagnetic wave in vacuum is given by $$E = \hat i40\cos \left( {kz - 6 \times {{10}^8}t} \right),$$ where $$E,z$$ and $$t$$ are in $$volt/m,$$ metre and second respectively. The value of wave vector $$k$$ is