JEE Main & Advanced
Physics
EM Waves
Question Bank
Numerical Value Type Questions - Electromagnetic Waves
question_answer
The electric field associated with an e.m. wave in vacuum is given by \[\overrightarrow{E}=\hat{i}40cos\left( kz-6\times {{10}^{8}}t \right),\]where E, z and t are in volt/m, meter and seconds respectively. The value of wave vector \[k\] \[\left( in\text{ }metr{{e}^{-1}} \right)\] is