JEE MAIN - Physics (2021 - 18th March Morning Shift - No. 3)
A plane electromagnetic wave of frequency 100 MHz is travelling in vacuum along the x-direction. At a particular point in space and time, $$\overrightarrow B = 2.0 \times {10^{ - 8}}\widehat kT$$. (where, $$\widehat k$$ is unit vector along z-direction) What is $$\overrightarrow E $$ at this point?
0.6 $$\widehat j$$ V/m
6.0 $$\widehat k$$ V/m
6.0 $$\widehat j$$ V/m
0.6 $$\widehat k$$ V/m
Explanation
f = 100 MHz
$$\overrightarrow B = 2 \times {10^{ - 8}}T$$
$$\overrightarrow E = \overrightarrow B \times \overrightarrow V $$
$$ = (2 \times {10^8}\widehat k) \times (3 \times {10^8}\widehat i)$$
$$ = 6(\widehat k \times \widehat i) = 6\widehat j$$ V/m
$$ \Rightarrow $$ $$\overrightarrow E = 6\widehat j$$ V/m
$$\overrightarrow B = 2 \times {10^{ - 8}}T$$
$$\overrightarrow E = \overrightarrow B \times \overrightarrow V $$
$$ = (2 \times {10^8}\widehat k) \times (3 \times {10^8}\widehat i)$$
$$ = 6(\widehat k \times \widehat i) = 6\widehat j$$ V/m
$$ \Rightarrow $$ $$\overrightarrow E = 6\widehat j$$ V/m
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