Question

If a pure resistance load, when connected to a lossless 75 ohm line, produces a VSWR of 3 on the line, then load impedance can only be 25 ohms

Answer 1

Ans : (b)

For a pure resistive load of a lossless line,

$VSWR=\frac{R_L}{R_0}if{R}_L>R_0$

$VSWR=\frac{R_0}{R_L}if{R}_0>R_L$

Given that, VSWR = 3

So, $R_L=VSWR\times R_0=3\times 75=225\Omega$

or $R_L=\frac{R_0}{VSWR}=\frac{75}{3}=25\Omega$

Hence, $R_L=25or75$