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)

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

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 )

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Important Questions on Waves

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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

A transverse wave propagating on a stretched string of linear density $3 \times 10^{- 4} {kgm}^{- 1}$ is represented by the equation

$y = 0.2 \sin (1.5 x + 60 t)$

where, $x$ in metres and $t$ is in seconds. The tension in the string (in Newton) is

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Physics>Waves and Oscillations>Waves>Classification of Waves

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

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Physics>Waves and Oscillations>Waves>Classification of Waves

The speed of sound in an elastic string when it is extended by $x m$ is $v .$ If it is further extended to $3 x m,$ the speed of the sound becomes

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Physics>Waves and Oscillations>Waves>Classification of Waves

A string of length

1 m

and mass

5 g

is fixed at both ends. The tension in the string is

8 .0 N

. The string is set into vibration using an external vibrator of frequency

100 Hz

. The separation between successive nodes on the string is close to

EASY

Physics>Waves and Oscillations>Waves>Classification of Waves

Which of the following is not a transverse wave?

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Physics>Waves and Oscillations>Waves>Classification of Waves

A steel wire has a length of

90 cm

which is under a constant tension of

100 N .

The speed of the transverse waves that can be produced in the wire will be (take the mass of the steel wire to be

6 \times 10^{- 3} kg

)

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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,

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Physics>Waves and Oscillations>Waves>Classification of Waves

A uniform rope of length

L

and mass

m_{1}

, hangs vertically from a rigid support. A block of mass

m_{2}

is attached to the free end of the rope. A transverse pulse of wavelength

λ_{1}

is produced at the lower end of the rope. The wavelength of the pulse when it reaches the top of the rope is

λ_{2}

. The ratio

\frac{λ_{2}}{λ_{1}}

is:

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	$10^{- 3} m$

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Physics>Waves and Oscillations>Waves>Classification of Waves

Draw a graph between displacement from mean position and time for a body executing free vibration in a vacuum.

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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

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Physics>Waves and Oscillations>Waves>Classification of Waves

Waves inside a gas are

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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)	$\sqrt{\frac{λ}{ρ}}$

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Physics>Waves and Oscillations>Waves>Classification of Waves

If the initial tension on a stretched string is doubled, then the ratio of the initial and final speeds of a transverse wave along the string is:

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Physics>Waves and Oscillations>Waves>Classification of Waves

The figure below shows pressure variation in two different sound waves in air with time at a given position. Both the figures are drawn to the same scale.

Question Image

Which of the following statement is true?

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Physics>Waves and Oscillations>Waves>Classification of Waves

A heavy ball of mass

M

is suspended from the ceiling of a car by a light string of mass

m (m ≪ M) .

When the car is at rest, the speed of transverse waves in the string is

60 m s^{- 1}

. When the car has acceleration

a

, the wave-speed increases to

60.5 m s^{- 1}

. The value of

a

in terms of gravitational acceleration

g

is closed to:

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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

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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:

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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.

The fact that radiosignals reach the earth from outside the atmosphere, was discovered accidently by

Important Questions on Waves

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