The correct match between the entries in column I and column II are : I II Radiation Wavelength a Microwave i 100 m b Gamma rays ii 10 - 15 m c A.M. radio iii 10 - 10 m d X–rays iv 10 - 3 m

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

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

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

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

Match the following: Column - I Column - II (a) Transverse wave through a steel rod (i) B + 4 3 η ρ (b) Longitudinal waves in earth's crust (ii) η ρ (c) Longitudinal waves through a steel rod (iii) 2 π T g λ (d) Ripples (iv) λ ρ

( a − i i ) , ( b − i ) , ( c − i v ) , ( d − i i i )

( a − i ) , ( b − i i i ) , ( c − i v ) , ( d − i i )

( a − i i i ) , ( b − i v ) , ( c − i ) , ( d − i i )

( a − i i ) , ( b − i v ) , ( c − i ) , ( d − i i i )

The electric field of a plane electromagnetic wave is given by E → = E 0 x ^ + y ^ sin k z - ω t . Its magnetic field will be given by

E 0 c - x ^ + y ^ sin k z - ω t

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Unpolarized light of intensity $I_{0}$ is incident on surface of a block of glass at Brewster's angle. In that case, which one of the following statements is true?

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Important Questions on Physics

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For an electromagnetic wave, which of the following statements is true?

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The correct match between the entries in column I and column II are :

	I		II
	Radiation		Wavelength
a	Microwave	i	$100 m$
b	Gamma rays	ii	$10^{- 15} m$
c	A.M. radio	iii	$10^{- 10} m$
d	X–rays	iv	$10^{- 3} m$

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A pendulum vibrates with a time period of

1

second. The sound produced in it is in the range of

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Which of the following is not a transverse wave?

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The electric field of a plane electromagnetic wave propagating along the x direction in vacuum is

\vec{E} = E_{0} jcos (ω t - kx) .

The magnetic field

\vec{B},

at the moment

t = 0

is:

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Match the following:

	Column $- I$		Column $- II$
(a)	Transverse wave through a steel rod	(i)	$\sqrt{B + (\frac{4}{3}) \frac{η}{ρ}}$
(b)	Longitudinal waves in earth's crust	(ii)	$\sqrt{\frac{η}{ρ}}$
(c)	Longitudinal waves through a steel rod	(iii)	$\sqrt{\frac{2 π T}{g λ}}$
(d)	Ripples	(iv)	$\sqrt{\frac{λ}{ρ}}$

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An electron is constrained to move along the

y

-axis with a speed of

0.1 c

(c is the speed of light) in the presence of electromagnetic wave, whose electric field is

\vec{E} = 30 \hat{j} \sin (1.5 \times 10^{7} t - 5 \times 10^{- 2} x) V m^{- 1} .

where

t

is in seconds and

x

is in meters. The maximum magnetic force experienced by the electron will be: (given

c = 3 \times 10^{8} m s^{- 1}

and electron charge

= 1.6 \times 10^{- 19} C

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A stretched string fixed at both ends has

n

nodes then the length of the string in terms of wavelength is

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Assume that the displacement

(s)

of air is proportional to the pressure difference

(Δ p)

created by a sound wave. Displacement

(s)

further depends on the speed of sound

(v)

, density of air

(ρ)

and the frequency

(f)

. If

Δ p = 10 Pa, n = 300 m s^{- 1}, p = 1 kg m^{- 3}

and

f = 1000 Hz

, then

s

will be of the order of (take the multiplicative constant to be

1

)

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The driver of bus approaching a big wall notices that the frequency of his bus's horn changes from

420 Hz

490 Hz

when he hears it after it gets reflected from the wall. Find the speed of the bus if speed of the sound is

330 {ms}^{- 1}

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When a sound wave is reflected from the boundary of a denser medium, the compression of the incident wave is returned as:

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A transverse wave travels on a taut steel wire with a velocity of

v

when tension in it is

2.06 \times 10^{4} N .

When the tension is changed to

T,

the velocity changed to

\frac{v}{2} .

The value of

T

is close to:

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A wave travelling on a string is described by

y = \sqrt{π} s i n (10 x - π t + \frac{π}{4})

. All the physical quantities are in SI units. The frequency of the wave is

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To propagate both longitudinal and transverse waves, a material must have

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Which waves are used in sonography?

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The magnetic field in a travelling electromagnetic wave has a peak value of

20 nT

. The peak value of electric field strength is,

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Pitch of the sound depends on

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In a resonance tube experiment when the tube is filled with water up to a height of

17.0 cm,

from bottom, it resonates with a given tuning fork. When the water level is raised the next resonance with the same tuning fork occurs at a height of

24.5 cm .

If the velocity of sound in air is

330 m s^{- 1},

the tuning fork frequency is :

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The electric field of a plane electromagnetic wave is given by $\vec{E} = E_{0} (\hat{x} + \hat{y}) \sin (k z - ω t)$ . Its magnetic field will be given by

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Given below in the left column are different modes of communication using the kinds of waves given in the right column.

(1) Optical Fibre Communication	(P) Ultrasound
(2) Radar	(Q) Infrared Light
(3) Sonar	(R) Microwaves
(4) Mobile Phones	(S) Radio Waves

From the options given below, find the most appropriate match between entries in the left and the right column.

Unpolarized light of intensity I0 is incident on surface of a block of glass at Brewster's angle. In that case, which one of the following statements is true?

Important Questions on Physics

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Unpolarized light of intensity $I_{0}$ is incident on surface of a block of glass at Brewster's angle. In that case, which one of the following statements is true?