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NEET - Grade 12 - Physics - Electromagnetic Waves - Introduction and Snapshot of Electromagnetic Waves - Study ref# 827

Introduction: In Chapter 4, we have learnt that an electric current produces magnetic field and that two current-carrying wires exert a magnetic force on each other. Further, in Chapter 6, we have seen that a magnetic field changing wi... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Introduction and Snapshot of Electromagnetic Waves - Study ref# 828

Following sections must be covered to understand the Electromagnetic Wave: 1. Introduction 2. Displacement Current 3. Electromagnetic Waves 4. Electromagnetic Spectrum... read more

NEET - Grade 12 - Physics - Ray Optics and Optical Instruments - Introduction and Snapshot of Ray Optics and Optical Instruments - Study ref# 830

Introduction: Nature has endowed the human eye (retinal) with the sensitivity to detect electromagnetic waves within a small range of the electromagnetic spectrum. Electromagnetic radiation belonging to this region of the spectrum (wav... read more

NEET - Grade 12 - Physics - Dual Nature of Radiation and Matter - Introduction and Snapshot of Dual Nature of Radiation and Matter - Study ref# 836

Introduction: The Maxwell’s equations of electromagnetism and Hertz experiments on the generation and detection of electromagnetic waves in 1887 strongly established the wave nature of light. Towards the same period at the end of 19th ... read more

NEET - Grade 12 - Physics - Communication Systems - Introduction and Snapshot of Communication Systems - Study ref# 849

Following sections must be covered to understand the Communication System: 1. Introduction 2. Elements of a Communication System 3. Basic Terminology Used in Electronic Communication Systems 4. Bandwidth of Signals 5. Bandwidt... read more

NEET - Grade 12 - Physics - Wave Optics - Introduction and Snapshot of Wave Optics - Study ref# 833

Introduction: In 1637 Descartes gave the corpuscular model of light and derived Snell’s law. It explained the laws of reflection and refraction of light at an interface. The corpuscular model predicted that if ray of light (on refracti... read more

NEET - Grade 12 - Physics - Wave Optics - Introduction and Snapshot of Wave Optics - Study ref# 834

Following sections must be covered to understand the Wave Optics: 1. Introduction 2. Huygens Principle 3. Refraction and reflection of plane waves using Huygens Principle 4. Coherent and Incoherent Addition of Waves 5. Inte... read more

NEET - Grade 11 - Physics - Waves - Importance and Snapshot of Waves - Study ref# 733

Introduction: If you drop a pebble in a pond of still water, the water surface gets disturbed. The disturbance does not remain confined to one place, but propagates outward along a circle. If you continue dropping pebbles in the pond, ... read more

NEET - Grade 11 - Physics - Waves - Importance and Snapshot of Waves - Study ref# 734

Following sections must be covered to understand the Waves: 1. Introduction 2. Transverse and longitudinal waves 3. Displacement relation in progressive wave 4. The speed of a travelling wave 5. The principle of superposition of ... read more

NEET - Grade 11 - Physics - Waves - Target Setup for Waves - Study ref# 735

Student requires to achieve the following milestones to get better grip over Waves. The milestones / targets are as follows:- Starting Point: Days 0Test TypeAppear on TestTarget TestsScorePractice Test000%Chapter Test000%Subject ... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Target Setup for Electromagnetic Waves - Study ref# 829

Student requires to achieve the following milestones to get better grip over Electromagnetic Wave. The milestones / targets are as follows: Starting Point: Days 0Test TypeAppear on TestTarget TestsScorePractice Test000%Chapter Te... read more

NEET - Grade 11 - Physics - Units and Measurements - Study ref# 15

Show dimensionally that the frequency n of transverse waves in a string of length l and mass per unit length m under a tension T is given by    Answer: Let us suppose that,  where K is a dimensionless constant and a, b, c are... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1038

Which type of waves do not require a material medium for propagation? Answer: Electromagnetic waves.... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1039

Is it possible to have longitudinal waves on a string? A transverse wave in a steel rod? Answer: No, because string is not stretchable. It can neither be compressed nor expanded. Yes, transverse waves are possible in a steel rod, because ... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1040

Sound waves from a point source are propagating n all directions. What will be the ratio of amplitudes at distances of 9 m and 25 m from the source? Answer: We know, intensity Hence,  ... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1041

What type of motion particles of a medium execute when a wave passes through the medium? Answer: Particles of the medium execute simple harmonic motion about their mean position.... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1042

Sound travels faster on a rainy day than on a dry day. Why? Answer: Presence of moisture in air decreases the density of air. Hence velocity of sound increases on a rainy day.... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1043

What characteristics of the medium determine the velocity of sound waves? Answer: The velocity f sound waves in a medium is determined by i)        Elasticity ii)      Density ... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1044

When a source moves at a speed greater than that of sound, will Doppler formula hold? What will happen? Answer: No, Doppler formula is only valid when Speed of source  speed of sound read more

NEET - Grade 11 - Physics - Waves - Study ref# 1045

What is the essential condition for the formation of beats? Answer: The difference in frequencies of the two sources should not exceed 10.... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1046

Can the wave functions  represent a wave motion? Answer: No, because in wave motion, the wave function is continuous, single valued, har... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1047

The thunder of lightening is heard some moments after the flash is seen. Explain. Answer: We know, velocity of sound in air = 332 m/s                  velocity of light in air is =  m/s so,... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1048

When we start filling an empty bucket with water, the pitch of sound produced goes on changing. Why? Answer: A bucket is treated as a pipe closed at one end. The frequency of the note produced is read more

NEET - Grade 11 - Physics - Waves - Study ref# 1049

Explain the factors on which the pitch of a stretched string depends? Answer: The factors on which the pitch of a stretched string depends are i)        Length of the string: the pitch read more

NEET - Grade 11 - Physics - Waves - Study ref# 1050

What are fundamental note and overtones? Answer:  When a source is sounded, it generally vibrates on more than one mode and therefore, emits tones of different frequencies.   The tone of lowest frequency is called the fundamental note and th... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1051

A standing wave is represented by  . If one of the component waves is what is the equation of the second component wave? Answer: We know,   ... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1052

Sound travels faster on a rainy day than on a dry day. Explain. Answer:   Dry air contains almost 79% nitrogen in it. The molecular weight of nitrogen is 28 gm. In rain day, water vapour is present in more amount than any dry day. Molecular ... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1053

Why is note produced by an open organ pipe sweeter than that produced by a closed organ pipe of same length? Answer: This is because, i)        The note produced by an open organ pipe consists of both the o... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1054

An incident wave is represented by  . Write the expression for reflected wave (i)     from a rigid boundary    (ii) from an open boundary. Answer: Incident wave is   read more

NEET - Grade 11 - Physics - Waves - Study ref# 1055

Is there a Doppler’s Effect for sound when the observer or the source move at right angles to the line joining them? Answer: When observer or source of sound moves through a small distance at right angles to the line joining them, there will b... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1056

Which characteristics of the medium determines the velocity of sound waves? Answer: (i)     Elasticity  and  (ii) density of the medium... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1057

The density of oxygen is 16 times the density of hydrogen. What is the ratio of speeds of sound in them? Answer:    ... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1058

Where to pluck and where to touch a stretched string to excite its first overtone? Answer: To excite the first overtone, the string must vibrate in two segments of equal length. Therefore, the string must be touched at its centre and ... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1059

An organ pipe is in resonance with a tuning fork. What change will have to be made in the length  to maintain resonance if (i)     Temperature increases

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NEET - Grade 11 - Physics - Waves - Study ref# 1060

Waves are generated on a water surface. Calculate the phase difference between two points A and B, when (i)     A and B lie on the same wave front at a distance =  between them.

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NEET - Grade 11 - Physics - Waves - Study ref# 1061

Set up a relation between speed of sound in a gas and root mean square velocity of the molecules of that gas. Answer: Speed of sound in a gas                   ----------- (i) According to... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1062

How will the fundamental frequency of a closed organ pipe be affected if instead of air, it is filled with a gas heavier than air? Answer: Th fundamental frequency of note produced by a closed organ pipe is              read more

NEET - Grade 11 - Physics - Waves - Study ref# 1063

There are two wires, each produces frequency of 500 Hz. By what percentage tension in one wire is increased so that 5 beats per second can be heard? Answer: We know, frequency of a stretched wire read more

NEET - Grade 11 - Physics - Waves - Study ref# 1064

A stretched wire emits a fundamental note of frequency 256 Hz. Keeping the stretching force constant and reducing the length of the wire by 10 cm, frequency becomes 320 Hz. Calculate original length of the wire. Answer: Suppose read more

NEET - Grade 11 - Physics - Waves - Study ref# 1065

A wave is expressed by the equation  where y and x are in metre and t in seconds. Find the speed of propagation. Answer: The given equation is  read more

NEET - Grade 11 - Physics - Waves - Study ref# 1066

Two vibrating modes of an air column are shown in figure. What is the ratio of frequency of two notes? Answer: Suppose length of air column is In mode (a),                       ... read more

NEET - Grade 11 - Physics - Waves - Study ref# 1067

Why stationary waves do not transport energy? Answer: Since nodes and antinodes formed remain stationary, the energy remains confined to one region. It cannot overcome the pressure maxima at nodes. So energy is not transmitted by standing waves.... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10583

Name the current which can flow even in the absence of electric charge. Answer: Displacement current... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10584

Professor C.V. Raman surprised his students by suspending freely a tiny light ball in a transparent vacuum chamber by shining a laser beam on it, Which property of EM waves was he exhibiting? Give one more examples of this property? Answer: ... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10585

In which directions do the electric and magnetic field vectors oscillate in an electromagnetic wave propagating along the x-axis? Answer: along y-axis andalong z-axis (Alternatively: read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10586

Write the expression for speed of electromagnetic waves in a medium of electrical permittivityand magnetic permeability. Answer: Formula                            Alternatively,                          ... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10587

Do electromagnetic waves carry energy and momentum? Answer: Yes Detailed Answer: EM waves carry energy and momentum without having mass and can exert pressure which is known as radiation pressure. These waves like other waves carry ... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10588

Write the relation for the speed of electromagnetic waves in terms of the amplitudes of electric and magnetic fields. Answer: Speed of electromagnetic wave,  ... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10589

A variable frequency ac source is connected to a capacitor. Will the displacement current change if the frequency of the ac source is decreased? Answer: It is noted that by dropping the variable frequency, there will be drop in displacement ... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10590

A capacitor has been charged by a dc source. What are the magnitude of conduction and displacement currents, when it is fully charged? Answer: The magnitude of conduction and displacement currents are zero. Detailed Answer: When a c... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10591

How does Ampere-Maxwell explain the flow of current through a capacitor when it is being charged by a battery? Write the expression for the displacement current in terms of the rate of change of electric flux. Answer: Explanation of flow of ... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10592

A plane electromagnetic wave of frequency 25 MHz travels in free space along the x=direction. At a particular point in space and time, .What is B at this point? Answer: The magnitude of B is                                            ... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10593

How does a charge q oscillating at certain frequency produce electromagnetic waves? Sketch a schematic diagram depicting electric and magnetic fields for an electromagnetic wave propagating along the Z-direction. Answer: When the motion o... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10594

(i) An EM wave is travelling in a medium with a velocity. Draw a sketch showing the propagation of the EM wave, indicating the direction of the oscillating electric and magnetic fields. (ii) How are the magnitudes of the electric and m... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10595

Why are microwaves considered suitable for radar systems used in aircraft navigation? Answer: Due to their short wavelength Detailed Answer: Microwaves are considered good for radar systems used in aircraft navigation as these wave hav... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10596

Name the electromagnetic radiations used for (a) water purification, and (b) eye surgery. Answer: (a) Ultra violet rays (b) Ultra violet rays/laser... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10597

Name the electromagnetic waves those are widely used as a diagnostic tool in medicine. Answer: X-rays... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10598

To which part of the electromagnetic spectrum does a wave of frequency belong? Answer: Infrared region. Detailed Answer: The frequency belong to infrared region of electromagnetic spe... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10599

Compare the following: (i) Wavelengths of the incident solar radiation absorbed by the earth’s surface and the radiation re-radiated by the earth. (ii) Tanning effect produced on the skin by UV radiation incident directly on the ski... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10600

Identify the electromagnetic waves whose wavelength vary as: (i)   (ii) Write one use for each. Answer: (i) Identification (ii)... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10601

Arrange the following electromagnetic radiations in ascending order to their frequencies: (i) Microwaves (ii) Radio waves (iii) X-rays (iv) Gamma rays Write two uses of any one of these. Answer: Radio waves < Microwaves < X... read more

NEET - Grade 12 - Physics - Electromagnetic Waves - Study ref# 10602

Name the type of EM waves having a wavelength range of 0.1m to 1mm. How are these waves generated? Write their two uses. Answer: Name of EM wave Method of generation Two uses Microwaves Produced by special vacuum tubes Klyston, m... read more

NEET - Grade 12 - Physics - Ray Optics and Optical Instruments - Study ref# 10603

The phenomena involved in the reflection of radio waves by ionosphere are similar to (a) reflection of light by a plane mirror (b) total internal reflection of light in air during a mirage. (c) dispersion of light by water molecules... read more

NEET - Grade 12 - Physics - Wave Optics - Study ref# 10628

Define the term wavefront. Answer: The locus of all points those are in the same phase. Wavefront is the locus of all points in which light waves are in same phase. Propagation of wave energy is perpendicular to the wavefront.... read more

NEET - Grade 12 - Physics - Wave Optics - Study ref# 10629

Differentiate between a ray and a wavefront. Answer: A ray is an imaginary path along which light energy propagates. Wavefont is locus of all points in which light waves are in same phase. Propagation of wave energy is perpendicular to... read more

NEET - Grade 12 - Physics - Wave Optics - Study ref# 10633

Define secondary wavelets and how can we construct new wavefront with them? Answer: According to the Huygen’s principle, every particle of the medium situated on the wavefront acts as a new source of light wave from which new similar waves o... read more

NEET - Grade 12 - Physics - Wave Optics - Study ref# 10634

(i) Define the term wavefront. State Huygen’s principle. (ii) Consider a plane wavefront incident on a thin convex lens. Draw a proper diagram to show how the incident wavefront traverses through the lens and after refraction focuses on t... read more

NEET - Grade 12 - Physics - Wave Optics - Study ref# 10636

Define the term ʹcoherent sourcesʹ which are required to produce interference pattern in Young’s double slit experiment. Answer: Two monochromatic sources, which produce light waves, having a constant phase difference, are known as... read more

NEET - Grade 12 - Physics - Communication Systems - Study ref# 10724

Why are microwaves considered suitable for radar systems used in aircraft navigation? Answer: Due to their short wavelengths, they are suitable for radar system used in aircraft navigation.... read more

NEET - Grade 12 - Physics - Communication Systems - Study ref# 10729

(i) What is line of sight communication? (ii) Why is it not possible to use sky waves for transmission of TV signals? Upto what distance can a signal be transmitted using an  antenna of height ‘h’? Answer: (i) Communication, using waves whi... read more

NEET - Grade 12 - Physics - Communication Systems - Study ref# 10730

Which basic mode of communication is used in satellite communication? What type of wave propagation is used in this mode? Write, giving reason, the frequency range used in this mode of propagation. Answer: Broadcast/point to point, mode of ... read more

NEET - Grade 12 - Physics - Communication Systems - Study ref# 10734

What is space wave propagation? Which systems of communication use space waves? What is ‘radio horizon’ of transmitting antenna of height h? Why is space wave propagation suitable for frequencies above 40 MHz? Answer: Propagation of waves, a... read more

NEET - Grade 12 - Physics - Communication Systems - Study ref# 10737

What is space wave propagation? State the factors which limit its range of propagation. Derive an expression for the maximum line of sight distance between two antennas for space wave propagation. Answer: Space Wave Propagation: The mo... read more

NEET - Grade 12 - Physics - Communication Systems - Study ref# 10739

How are side bands produced? Answer: Side bands are produced due to the superposition of carrier waves of frequency  over modulating /audio signal of frequency  .... read more

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