Which of the following statements is NOT true | vedclass

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(B) The power $P$ radiated by a linear antenna is given by the relation $P \propto \frac{l^2}{\lambda^2}$,where $l$ is the length of the antenna and $

Vedclass · Accepted Answer

Power radiated decreases with increasing frequency.

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(B) The power $P$ radiated by a linear antenna is given by the relation $P \propto \frac{l^2}{\lambda^2}$,where $l$ is the length of the antenna and $\lambda$ is the wavelength.Since $P \propto l^2$,statement $A$ is true.Since $\lambda = \frac{c}{f}$,we have $P \propto \frac{l^2}{(c/f)^2} \propto f^2$. This means power radiated increases with the square of the frequency.Therefore,statement $B$ is false because it claims power decreases with increasing frequency.For efficient radiation,the antenna size $l$ must be comparable to the wavelength $\lambda$ (typically $l \geq \frac{\lambda}{4}$),so statement $C$ is true.Since long wavelength signals correspond to low frequencies,the radiated power $P \propto f^2$ is very small,making statement $D$ true.

Which of the following statements is $NOT$ true?

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