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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In the experiment for the determination of the speed of sound in air using the resonance column method, the length of the air column that resonates in the fundamental mode with a tuning fork is 0.1 m. When this length is changed to 0.35 m, the same tuning fork resonates with the first overtone. The end correction is

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Important Questions on Waves

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Physics>Waves and Oscillations>Waves>Classification of Waves

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

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

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	$10^{- 3} m$

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

A pendulum vibrates with a time period of

1

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

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

Which of the following is not a transverse wave?

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

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:

MEDIUM

Physics>Waves and Oscillations>Waves>Classification of Waves

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)	$\sqrt{\frac{λ}{ρ}}$

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

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

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

A stretched string fixed at both ends has

n

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

MEDIUM

Physics>Waves and Oscillations>Waves>Classification of Waves

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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Physics>Waves and Oscillations>Waves>Classification of Waves

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}

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

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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Physics>Waves and Oscillations>Waves>Classification of Waves

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:

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

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

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

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

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Physics>Waves and Oscillations>Waves>Classification of Waves

Which waves are used in sonography?

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Physics>Waves and Oscillations>Waves>Classification of Waves

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

20 nT

. The peak value of electric field strength is,

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

Pitch of the sound depends on

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

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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Physics>Waves and Oscillations>Waves>Classification of Waves

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

MEDIUM

Physics>Waves and Oscillations>Waves>Classification of Waves

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.

Important Questions on Waves

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