1
JEE Main 2015 (Online) 11th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
For plane electromagnetic waves propagating in the z direction, which one of the following combination gives the correct possible direction for $$\overrightarrow E $$ and $$\overrightarrow B $$ field respectively ?
A
$$\left( {\widehat i + 2\widehat j} \right)\,\,$$ and $$\left( {2\widehat i - \widehat j} \right)$$
B
$$\left(-\, {2\widehat i - 3\widehat j} \right)$$ and $$\left( {3\widehat i - 2\widehat j} \right)$$
C
$$\left( {2\widehat i + 3\widehat j} \right)$$ and $$\left( {\widehat i + 2\widehat j} \right)$$
D
$$\left( {3\widehat i + 4\widehat j} \right)$$ and $$\left( {4\widehat i - 3\widehat j} \right)$$
2
JEE Main 2015 (Online) 10th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
An electromagnetic wave travelling in the x-direction has frequency of 23 $$ \times $$ 1014 Hz and electric field amplitude of 27 Vm$$-$$1. From the options given below, which one describes the magnetic field for this wave ?
A
$$\overrightarrow B $$ (x, t) = (3 $$ \times $$ 10$$-$$8T) $$\widehat j$$

sin [ 2$$\pi $$ (1.5 $$ \times $$ 10$$-$$8x $$-$$ 2 $$ \times $$ 1014t)]
B
$$\overrightarrow B $$ (x, t) = (9 $$ \times $$ 10$$-$$8T) $$\widehat k$$

sin [ 2$$\pi $$ (1.5 $$ \times $$ 10$$-$$6x $$-$$ 2 $$ \times $$ 1014t)]
C
$$\overrightarrow B $$ (x, t) = (9 $$ \times $$ 10$$-$$8T) $$\widehat i$$

sin [ 2$$\pi $$ (1.5 $$ \times $$ 10$$-$$8x $$-$$ 2 $$ \times $$ 1014t)]
D
$$\overrightarrow B $$ (x, t) = (9 $$ \times $$ 10$$-$$8T) $$\widehat j$$

sin [(1.5 $$ \times $$ 10$$-$$6 x $$-$$ 2 $$ \times $$ 1014t)]
3
JEE Main 2026 (Online) 6th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

For an electromagnetic wave propagating through vacuum, $\vec{k}, \vec{E}$ and $\omega$ represent propagation vector, electric field and angular frequency, respectively. The magnetic field associated with this wave is represented by:

A

$\frac{\vec{E} \times \vec{k}}{\omega}$

B

$\frac{\vec{k} \times \vec{E}}{\omega}$

C

$\omega(\vec{E} \times \vec{k})$

D

$\omega(\vec{k} \times \vec{E})$

4
JEE Main 2026 (Online) 6th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A point light source emits E.M. waves in free space. A detector, placed at a distance of $L \mathrm{~m}$, measures the intensity as $I_{\mathrm{o}}$. The detector is now shifted to another location on the same spherical surface ensuring the angle between original location and new location as $45^{\circ}$. The measured intensity at new location will be $\_\_\_\_$ .

A

$\frac{I_{\mathrm{o}}}{4}$

B

$I_{\mathrm{o}}$

C

$\frac{I_0}{\sqrt{2}}$

D

${\frac{I_{\mathrm{o}}}{2}}$

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