JEE Main 2022 (Online) 28th June Morning Shift | Electromagnetic Waves Question 57 | Physics

JEE Main 2022 (Online) 28th June Morning Shift

MCQ (Single Correct Answer)

-1

A radar sends an electromagnetic signal of electric field (E₀) = 2.25 V/m and magnetic field (B₀) = 1.5 $$\times$$ 10^$$-$$8 T which strikes a target on line of sight at a distance of 3 km in a medium. After that, a part of signal (echo) reflects back towards the radar with same velocity and by same path. If the signal was transmitted at time t = 0 from radar, then after how much time echo will reach to the radar?

2.0 $$\times$$ 10^$$-$$5 s

4.0 $$\times$$ 10^$$-$$5 s

1.0 $$\times$$ 10^$$-$$5 s

8.0 $$\times$$ 10^$$-$$5 s

JEE Main 2022 (Online) 27th June Evening Shift

MCQ (Single Correct Answer)

-1

Given below are two statements :

Statement I : A time varying electric field is a source of changing magnetic field and vice-versa. Thus a disturbance in electric or magnetic field creates EM waves.

Statement II : In a material medium, the EM wave travels with speed $$v = {1 \over {\sqrt {{\mu _0}{ \in _0}} }}$$. In the light of the above statements, choose the correct answer from the options given below.

Both Statement I and Statement II are true

Both Statement I and Statement II are false

Statement I is correct but Statement II is false

Statement I is incorrect but Statement II is true

JEE Main 2022 (Online) 27th June Morning Shift

MCQ (Single Correct Answer)

-1

Match List-I with List-II :

	List - I		List - II
(a)	Ultraviolet rays	(i)	Study crystal structure
(b)	Microwaves	(ii)	Greenhouse effect
(c)	Infrared rays	(iii)	Sterilizing surgical instrument
(d)	X-rays	(iv)	Radar system

Choose the correct answer from the options given below :

(a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)

(a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)

(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)

JEE Main 2022 (Online) 26th June Evening Shift

MCQ (Single Correct Answer)

-1

Which is the correct ascending order of wavelengths?

$$\lambda$$_visible < $$\lambda$$_X-ray < $$\lambda$$_gamma-ray < $$\lambda$$_microwave

$$\lambda$$_gamma-ray < $$\lambda$$_X-ray < $$\lambda$$_visible < $$\lambda$$_microwave

$$\lambda$$_X-ray < $$\lambda$$_gamma-ray < $$\lambda$$_visible < $$\lambda$$_microwave

$$\lambda$$_microwave < $$\lambda$$_visible < $$\lambda$$_gamma-ray < $$\lambda$$_X-ray

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