Question
Long distance short-wave radio broadcasting uses

Answer

(c)

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where $\gamma$ is the ratio of specific heats):
A force of magnitude $50\, N$ acting along $\widehat i + \widehat j + \widehat k$, displaces a point mass from $(5, 9, 7)$ to $(4, 8, 6)$. The work done by this force during this displacement is :-
For a $CE$ transistor amplifier, the audio signal voltage across the collector resistance of $2.0\,k \Omega$ is $2.0\,V$. Suppose the current amplification factor of the transistor is $100$ , What should be the value of $R_B$ (in $k \Omega$) in series with $V_{B B}$ supply of $2.0\,V$ if the $dc$ base current has to be $10$ times the signal current?
An $ac$ source of angular frequency $\omega$ is fed across a resistor r and a capacitor $C$ in series. The current registered is $I$. If now the frequency of source is changed to $\omega$ $/3$ (but maintaining the same voltage), the current in then circuit is found to be halved. Calculate the ratio of reactance to resistance at the original frequency $\omega$
Carbon, Silicon and Germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by $(E_g)_C$, $(E_g)_{Si}$ and $(E_g)_{Ge}$ respectively. Which one of the following relationship is true in their case?
On increasing the length by $0.5\, mm$ in a steel wire of length $2\, m$ and area of cross-section $2\,m{m^2}$, the force required is $[Y$ for steel$ = 2.2 \times {10^{11}}\,N/{m^2}]$
Two capacitors ${C_1} = 2\,\mu \,F$ and ${C_2}\, = \,6\,\mu \,F$ in series, are connected in parallel to a third capacitor ${C_3} = \,4\,\mu \,F$. This arrangement is then connected to a battery of $e.m.f.$ $=$ $2V$, as shown in the figure. How much energy is lost by the battery in charging the capacitors
For adjoining fig., The magnetic field at point, $P$ will be
Three rings each of mass $M$ and radius $R$ are arranged as shown in the figure. The moment of inertia of the system about $YY' $ will be 
The radius of the convex surface of plano-convex lens is $20 cm$ and the refractive index of the material of the lens is $1.5.$ The focal length of the lens is......$cm$