The electron density of $E, F_1, F_2$ layers of the ionosphere is $2 \times 10^{11} \, m^{-3}$,$5 \times 10^{11} \, m^{-3}$,and $8 \times 10^{11} \, m^{-3}$ respectively. What is the ratio of critical frequencies for the reflection of radio waves?

  • A
    $2 : 4 : 3$
  • B
    $4 : 3 : 2$
  • C
    $2 : 3 : 4$
  • D
    $3 : 2 : 4$

Explore More

Similar Questions

Consider telecommunication through optical fibres. Which of the following statements is $NOT$ true?

If the maximum and minimum voltages of an $A.M.$ wave are $V_{\max}$ and $V_{\min}$ respectively,then the modulation factor '$m$' is

Match Column $A$ (layers in the ionosphere for skywave propagation) with Column $B$ (their height range).
Column $A$Column $B$
$A$. $D$-layer$I$. $250-400 \ km$
$B$. $E$-layer$II$. $170-190 \ km$
$C$. $F_1$-layer$III$. $95-120 \ km$
$D$. $F_2$-layer$IV$. $65-75 \ km$

When the angle of incidence is $74^{\circ}$,the critical frequency of the $F$ layer is $50 \text{ MHz}$. What is the Maximum Usable Frequency $(MUF)$ in $\text{ MHz}$ (in $.5$)?

Difficult
View Solution

$A$ $100\,m$ long antenna is mounted on a $500\,m$ tall building. The complex can become a transmission tower for waves with $\lambda$ (approx) ........ $m$.

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo