This is an Example of Step-up Transformer . - Physics (Theory)

Advertisements
Advertisements
Answer in Brief
One Line Answer

This is an example of step-up transformer .

Advertisements

Solution

(i) Microwaves may be reflected, refracted and attenuated by certain substances.

(ii) Microwaves have low frequency and high wavelength.

  Is there an error in this question or solution?
2018-2019 (March) Set 1

Video TutorialsVIEW ALL [2]

RELATED QUESTIONS

Write any two important properties of electromagnetic waves.


The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is B0 = 510 nT. What is the amplitude of the electric field part of the wave?


Do electromagnetic waves carry energy and momentum ?


What is the ratio of the speed of gamma rays to that of radio waves in a vacuum?


How are electric vector `(vec "E")`, magnetic vector `(vec "B")` and velocity vector `(vec "C")` oriented in an electromagnetic wave?


A plane electromagnetic wave is travelling through a medium along the +ve z-direction. Depict the electromagnetic wave showing the directions of the oscillating electric and magnetic fields.


How does oscillating charge produce electromagnetic waves?


Write the following radiations in ascending order with respect to their frequencies:

X-rays, microwaves, UV rays and radio waves.


Can an electromagnetic wave be deflected by an electric field or a magnetic field?


A wire carries an alternating current i = i0 sin ωt. Is there an electric field in the vicinity of the wire?


A capacitor is connected to an alternating-current source. Is there a magnetic field between the plates?


Can an electromagnetic wave be polarised?


A plane electromagnetic wave is passing through a region. Consider (a) electric field (b) magnetic field (c) electrical energy in a small volume and (d) magnetic energy in a small volume. Construct the pairs of the quantities that oscillate with equal frequencies.


An electromagnetic wave going through vacuum is described by
E = E0 sin (kx − ωt); B = B0 sin (kx − ωt).
Which of the following equations is true?


Speed of electromagnetic waves is the same


Which of the following have zero average value in a plane electromagnetic wave?
(a) Electric field
(b) Magnetic field
(c) Electric energy
(d) Magnetic energy


The energy contained in a small volume through which an electromagnetic wave is passing oscillates with


Consider the situation of the previous problem. Define displacement resistance Rd = V/idof the space between the plates, where V is the potential difference between the plates and id is the displacement current. Show that Rd varies with time as `R_d = R(e^(t"/"tau) - 1)` .


The energy associated with light of which of the following colours is minimum : 


Define frequency modulation and state any one advantage of frequency modulation (FM) over amplitude modulation (AM). 


State any one property which is common to all electromagnetic waves.


The energy levels of an atom of a certain element are shown in the given figure. Which one of the transitions A, B, C, D or E will result in the emission of photons of electromagnetic radiation of wavelength 618.75 nm? Support your answer with mathematical calculations.


In an electromagnetic wave in free space the rms value of the electric field is 3 V m-1. The peak value of the magnetic field is ______.


An e.m. wave is propagating in a medium with a velocity `vec"v" = "v" hat"i"`. The instantaneous oscillating electric field of this e.m. wave is along +y-axis, then the direction of an oscillating magnetic field of the e.m. wave will be along:


Let E = E0 sin[106 x -ωt] be the electric field of plane electromagnetic wave, the value of ω is ______.


What is displacement current?


Write notes on Ampere-Maxwell law.


Why are e.m. waves non-mechanical?


Write down Maxwell equations in integral form.


Write a short note on the radio waves.


Write down the properties of electromagnetic waves.


Consider a parallel plate capacitor whose plates are closely spaced. Let R be the radius of the plates and the current in the wire connected to the plates is 5 A, calculate the displacement current through the surface passing between the plates by directly calculating the rate of change of flux of electric field through the surface.


Maxwell’s displacement current is a response to inconsistency in the ______.


The magnetic field of a plane electromagnetic wave travelling in +ve z-direction is described by ______.


Radio waves for FM radio have a frequency about ______.


A man standing on the road has to hold his umbrella at 30° with the vertical to keep the rain away. He throws away the umbrella and starts, running at 10 km/h and finds raindrops hitting his head vertically. The speed of the raindrops with respect to the road is ______.


Which one of the following does not represent simple harmonic motion? Here y denotes the instantaneous displacement. Here, A and B are constants and co is the angular frequency.


A plane electromagnetic wave travels in free space along x-axis. At a particular point in space, the electric field along y-axis is 9.3 Vm−1. The magnetic induction (B) along z-axis is:


Which of the following electromagnetic radiations has the smallest wave length?


Maxwell's equation describe the fundamental law of


If a source is transmitting electromagnetic waves of frequency 8.2 × 106 Hz. then wavelength of electromagnetic waves transmitted from the source will be.


The velocity of light in vacuum can be changed by changing


Which of the following are not electromagnetic waves?


The sun delivers 103w/m2 of electromagnetic flux to the earth's surface. The total power that is incident on a roof of dimension 8m/10m will be


Electromagnetic waves are produced by ______.


Which of the following type of radiations are radiated by an oscillating electric charge?


For a plane electromagnetic wave propagating in x-direction, which one of the following combinations gives the correct possible directions for electric field (E) and magnetic field (B) respectively?


For a plane electromagnetic wave propagating in the x-direction, which one of the following combinations gives the correct possible directions for the electric field (E) and magnetic field (B) respectively?


If `vecE` and `vecB` represent electric and magnetic field vectors of the electromagnetic wave, the direction of propagation of the electromagnetic wave is along ______.


Show that the radiation pressure exerted by an EM wave of intensity I on a surface kept in vacuum is I/c.


The intensity of the light from a bulb incident on a surface is 0.22 W/m2 . The amplitude of the magnetic field in this light-wave is ______× 10–9 T. 

(Given: Permittivity of vacuum ε0 = 8.85 × 10–12 C2 N–1 – m–2, speed of light in vacuum c = 3 × 108 ms-1)


For an electromagnetic wave travelling in free space, the relation between average energy densities due to electric (Ue) and magnetic (Um) fields is ______.


A plane electromagnetic wave travels in free space along the x-direction. The electric field component of the wave at a particular point of space and time is E = 6 Vm-1 along the y-direction. Its corresponding magnetic field component, B would be ______.


Sunlight falls normally on a surface of area 36 cm2 and exerts an average force of 7.2 × 10-9 N within a time period of 20 minutes. Considering a case of complete absorption the energy flux of incident light is ______.


The electric field in an electromagnetic wave is given by E = 56.5 sin ω(t - x/c)Nc-1. Find the intensity of the wave if it is propagating along x-axis in the free space.

(Given ε0 = 8.85 × 10-12 C2 N-1 m-2)


A plane electromagnetic wave with frequency of 30 MHz travels in free space. At particular point in space and time, electric field is 6 V/m. The magnetic field at this point will be x × 10-8 T. The value of x is ______.


An electromagnetic wave of frequency 3 GHz enters a dielectric medium of relative electric permittivity 2.25 from vacuum. The wavelength of this wave in that medium will be ______ × 10-2 cm. 


In a plane electromagnetic wave, the direction of electric field and magnetic field are represented by `hat"k"` and 2`hat"i" - 2hat"j"`, respectively. What is the unit vector along direction of propagation of the wave.


A 27 mW laser beam has a cross-sectional area of 10 mm2. The magnitude of the maximum electric field in this electromagnetic wave is given by:

[Given permittivity of space ∈0 = 9 × 10-12 SI units, Speed of light c = 3  108 m/s] 


An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into a dielectric medium with permittivity ∈ = 4.0. Then ______.


Name the electromagnetic wave/radiation which is used to study crystal structure.


Share
Notifications



      Forgot password?
Use app×