Question

The antenna current of an `AM` transmitter is `8A` when only the carrier is sent but increases to `8.96A` when the carrier is modulated sinusoidally . The percentage modulation is
A. `50%`
B. `60%`
C. `65%`
D. `71%`

Answer 1

Correct Answer - d
We known that `((I_(t))/(I_(c)))^(2) =1+(m^(2))/(2)`
Here, `I_(t)=8.96 A` and `I_(c)=8.4`
`:. ((8.96)/(8))^(2)=1+(m^(2))/(2)` or `1.254 =1+(m^(2))/(2)`
or `(m^(2))/(2)=0.254` or `m^(2)=0.508`
or `m=0.71=71%`