+1 vote
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An antenna of length 25 m is mounted on top of a building of height 75 m. Then the maximum wavelength of the transmission signal is close to :

(1) 100 m          (2) 200 m         (3) 300 m         (4) 400 m
in Physics
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+1 vote
Length of antenna $$\ge {\lambda\over 4}$$
$$\lambda \le 4\times25$$
$$\lambda \le100m$$