The electron in the hydrogen atom is moving with a speed of 2 . 3 × 10 6 m s - 1 in an orbit of 0 . 53 A 0 . Calculate the period of revolution of electron. π = 3 . 142

Given : Speed of the electron in the hydrogen atom, v = 2 . 3 × 10 6 m s - 1 . The radius of the orbit, r = 0 . 53 A 0 = 0 . 53 × 10 - 10 m . The period of revolution of the electron, T = 2 π r v = 2 × 3 . 142 × 0 . 53 × 10 - 10 2 . 3 × 10 6 = 1 . 44 × 10 - 16 s .

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

Complete the table using given statements associated with waves. Particles vibrate in a direction parallel to the direction of propagation of waves. Formed on the surface of solids and liquids. Crests and troughs are formed. Compression and rarefactions are formed. Longitudinal waves Transverse waves

Longitudinal waves Transverse waves Particles vibrate in a direction parallel to the direction of propagation of waves. Formed on the surface of solids and liquids. Compression and rarefactions are formed. Crests and troughs are formed. Longitudinal waves are those waves in which particles vibrate parallel to the propagation of the waves. In case of transverse waves, the particles vibrate perpendicular to direction of propagation of the wave.

EASY

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What type of waves are produced in a slinky and strings of violin?

Important Questions on Sound

HARD

Science>Physics>Sound>Propagation of Sound

The total length of a sonometer wire fixed between two bridges is

110 cm

. Now, two more bridges are placed to divide the length of the wire in the ratio

6 : 3 : 2

. If the tension in the wire is

400 N

and the mass per unit length of the wire is

0.01 kg m^{- 1}

, then the minimum common frequency with which all the three parts can vibrate, is

MEDIUM

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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,

EASY

Science>Physics>Sound>Propagation of Sound

In sonometer experiment, the string of length

L

under tension vibrates in second overtone between two bridges. The amplitude of vibration is maximum at

MEDIUM

Science>Physics>Sound>Propagation of Sound

A string is clamped at both the ends and it is vibrating in its

4^{t h}

harmonic. The equation of the stationary wave is

y = 0.3 \sin (0.157 x) c o s (200 π t)

. The length of the string is
(All quantities are in

S I

units.)

EASY

Science>Physics>Sound>Propagation of Sound

The wave having compression and rarefaction is known as

MEDIUM

Science>Physics>Sound>Propagation of Sound

A wire of length

2 L,

is made by joining two wires

A

and

B

of same length but different radii

r

and

2 r

and made of the same material. It is vibrating at a frequency such that the joint of the two wires forms a node. If the number of antinodes in wire

A

p

and that in

B

q

then ratio

p : q

is:

EASY

Science>Physics>Sound>Propagation of Sound

A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencier between these two. The lowest resonant frequency for this string is:

HARD

Science>Physics>Sound>Propagation of Sound

Find the wrong statement form the following about the equation of stationary wave given by

Y = 0.04 \cos (π x) \sin (50 π t)

m where

t

is in second. Then for the stationary wave.

EASY

Science>Physics>Sound>Propagation of Sound

The electron in the hydrogen atom is moving with a speed of

2.3 \times 10^{6} m s^{- 1}

in an orbit of

0.53 \overset{0}{A}

. Calculate the period of revolution of electron.

(π = 3.142)

MEDIUM

Science>Physics>Sound>Propagation of Sound

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

MEDIUM

Science>Physics>Sound>Propagation of Sound

n_{1}, n_{2}

and

n_{3}

are the fundamental frequencies of three segments into which a string is divided, then the original fundamental frequency

n

of the string is given by:

EASY

Science>Physics>Sound>Propagation of Sound

If the frequency of wave is tripled, then its wave length:

EASY

Science>Physics>Sound>Propagation of Sound

A stretched string fixed at both ends has

m

nodes, then the length of the string will be

MEDIUM

Science>Physics>Sound>Propagation of Sound

A granite rod of

60 cm

length is clamped at its middle point and is set into longitudinal vibrations. The density of granite is

2.7 \times 10^{3} kg m^{- 3}

and its Young's modulus is

9.27 \times 10^{10} Pa

. What will be the fundamental frequency of the longitudinal vibrations?

EASY

Science>Physics>Sound>Propagation of Sound

A stretched wire of length

260 cm

is set into vibrations. It is divided into three segments whose frequencies are in the ratio

2 : 3 : 4

. Their lengths must be

MEDIUM

Science>Physics>Sound>Propagation of Sound

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

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A wire of length

L

and mass per unit length

6.0 \times 10^{- 3} k g m^{- 1}

is put under tension of

540 N .

Two consecutive frequencies that it resonates at are:

420 H z

and

490 H z .

Then

L

in meters is :

EASY

Science>Physics>Sound>Propagation of Sound

Complete the table using given statements associated with waves.

Particles vibrate in a direction parallel to the direction of propagation of waves.
Formed on the surface of solids and liquids.
Crests and troughs are formed.
Compression and rarefactions are formed.

Longitudinal waves	Transverse waves

EASY

Science>Physics>Sound>Propagation of Sound

Waves inside a gas are

MEDIUM

Science>Physics>Sound>Propagation of Sound

The linear distance between a consecutive compression and rarefaction in longitudinal wave is

What type of waves are produced in a slinky and strings of violin?

Important Questions on Sound

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