Question

For a radio signal to travel $150\, km$ from the transmitter to a receiving antenna, it takes

• A. $5 \times 10^{-4} s$
• B. $4.5 \times 10^{-3} s$
• C. $5 \times 10^{-8} s$
• D. $4.5 \times 10^{-6} s$

Answer 1

Answer: (A)

Velocity of radio wave is $3 \times 10^{8} m / s$
Timer $=\frac{\text { Distance }}{\text { time}}=\frac{150 \times 1000}{3 \times 10^{8}-2}$
$=5 \times 10^{-4} s$