English

Answer briefly. What are radio waves?

Advertisements
Advertisements

Question

Answer briefly.

What are radio waves?

Short/Brief Note
Advertisements

Solution

  1. Radio waves are produced by accelerated motion of charges in a conducting wire. The frequency of waves produced by the circuit depends upon the magnitudes of the inductance and the capacitance.
  2. Thus, by choosing suitable values of the inductance and the capacitance, radio waves of the desired frequency can be produced.
shaalaa.com
  Is there an error in this question or solution?
Chapter 13: Electromagnetic Waves and Communication System - Exercises [Page 241]

APPEARS IN

Balbharati Physics [English] Standard 11 Maharashtra State Board
Chapter 13 Electromagnetic Waves and Communication System
Exercises | Q 2. (ix) | Page 241

Video TutorialsVIEW ALL [2]

RELATED QUESTIONS

If the earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now? Explain.


Given below are some famous numbers associated with electromagnetic radiations in different contexts in physics. State the part of the electromagnetic spectrum to which each belongs.

(a) 21 cm (wavelength emitted by atomic hydrogen in interstellar space).

(b) 1057 MHz (frequency of radiation arising from two close energy levels in hydrogen; known as Lamb shift).

(c) 2.7 K [temperature associated with the isotropic radiation filling all space-thought to be a relic of the ‘big-bang’ origin of the universe].

(d) 5890 Å - 5896 Å [double lines of sodium]

(e) 14.4 keV [energy of a particular transition in 57Fe nucleus associated with a famous high resolution spectroscopic method (Mössbauer spectroscopy)].


Give a reason for the following:

It is necessary to use satellites for long-distance TV transmission. Why?


Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the earth. Why?


Name the phenomenon which shows the quantum nature of electromagnetic radiation.


A wave has wavelength 50 Å.

  1. Name the wave.
  2. State its speed in vacuum.
  3. State its one use.

State Moseley's law


Arrange the following radiations in the order of their increasing wavelength:

X-rays, infrared rays, ratio waves, gamma ray and microwaves.


Which radiation is used for satellite communication?


State the approximate range of wavelength associated with visible light.


Give one use of gamma rays.


Two waves A and B have wavelength 0.01 Å and 9000 Å respectively.

  1. Name the two waves.
  2. Compare the speeds of these waves when they travel in vacuum.

Which part of electromagnetic spectrum is used in radar systems?


Is it possible that in a Coolidge tube characteristic Lα X-rays are emitted but not Kα X-rays?


X-ray from a Coolidge tube is incident on a thin aluminium foil. The intensity of the X-ray transmitted by the foil is found to be I0. The heating current is increased to increase the temperature of the filament. The intensity of the X-ray transmitted by the foil will be
(a) zero
(b) < I0
(c) I0
(d) > I0


Cutoff wavelength of X-rays coming from a Coolidge tube depends on the
(a) target material
(b) accelerating voltage
(c) separation between the target and the filament
(d) temperature of the filament.


If the operating potential in an X-ray tube is increased by 1%, by what percentage does the cutoff wavelength decrease?

(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)


Name the scientist who discovered
 X-rays


Gamma rays and radio waves travel with the same velocity in free space. Distinguish between them in terms of their origin and the main application.


Give one use of electromagnetic radiation in Microwaves.


Choose the correct option.

The EM wave emitted by the Sun and responsible for heating the Earth’s atmosphere due to greenhouse effect is


Choose the correct option.

Earth’s atmosphere is richest in


Answer briefly.

Name the most harmful radiation entering the Earth's atmosphere from outer space.


X-rays, gamma rays and microwaves travelling in a vacuum have ______.


A bat moving at 10 ms−1 towards a wall sends a sound signal of 8000 Hz towards it. On reflection, it hears a sound of frequency f The value of f in Hz is close to (speed of sound = 320 ms−1)


Find the photon energy in units of ev for electromagnetic wave if waves length 40 m. Given h = 6.63 × 10–34 J.


What is time period of the light for which the eye is most sensitive?


The electric field intensity produced by the radiations coming from 100 W bulb at a 3 m distance is E. The electric field intensity produced by the radiations coming from 50 W bulb at the same distance is ______.


Why does microwave oven heats up a food item containing water molecules most efficiently?


Identify the part of the electromagnetic spectrum which:

  1. produces the heating effect.
  2. is absorbed by the ozone layer in the atmosphere.
  3. is used for studying crystal structure.

Write any one method of the production of each of the above radiations.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×