JEE Main 2014 (Online) 12th April Morning Slot | Electromagnetic Waves Question 4 | Physics

JEE Main 2014 (Online) 12th April Morning Slot

MCQ (Single Correct Answer)

-1

A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100 W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 5 m from the lamp will be nearly :

1.34 V/m

2.68 V/m

4.02 V/m

5.36 V/m

JEE Main 2014 (Online) 19th April Morning Slot

MCQ (Single Correct Answer)

-1

If microwaves, X rays, infracted, gamma rays, ultra-violet, radio waves and visible parts of the electromagnetic spectrum by M, X, I, G, U, R and V, the following is the arrangement in ascending order of wavelength :

R, M, I, V, U, X and G

M, R, V, X, U, G and I

G, X, U, V, I, M and R

I, M, R, U, V, X and G

JEE Main 2015 (Online) 10th April Morning Slot

MCQ (Single Correct Answer)

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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 ?

$$\overrightarrow B $$ (x, t) = (3 $$ \times $$ 10^$$-$$8T) $$\widehat j$$

sin [ 2$$\pi $$ (1.5 $$ \times $$ 10^$$-$$8x $$-$$ 2 $$ \times $$ 10¹⁴t)]

$$\overrightarrow B $$ (x, t) = (9 $$ \times $$ 10^$$-$$8T) $$\widehat k$$

sin [ 2$$\pi $$ (1.5 $$ \times $$ 10^$$-$$6x $$-$$ 2 $$ \times $$ 10¹⁴t)]

$$\overrightarrow B $$ (x, t) = (9 $$ \times $$ 10^$$-$$8T) $$\widehat i$$

sin [ 2$$\pi $$ (1.5 $$ \times $$ 10^$$-$$8x $$-$$ 2 $$ \times $$ 10¹⁴t)]

$$\overrightarrow B $$ (x, t) = (9 $$ \times $$ 10^$$-$$8T) $$\widehat j$$

sin [(1.5 $$ \times $$ 10^$$-$$6 x $$-$$ 2 $$ \times $$ 10¹⁴t)]

JEE Main 2015 (Online) 11th April Morning Slot

MCQ (Single Correct Answer)

-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 ?

$$\left( {\widehat i + 2\widehat j} \right)\,\,$$ and $$\left( {2\widehat i - \widehat j} \right)$$

$$\left(-\, {2\widehat i - 3\widehat j} \right)$$ and $$\left( {3\widehat i - 2\widehat j} \right)$$

$$\left( {2\widehat i + 3\widehat j} \right)$$ and $$\left( {\widehat i + 2\widehat j} \right)$$

$$\left( {3\widehat i + 4\widehat j} \right)$$ and $$\left( {4\widehat i - 3\widehat j} \right)$$

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