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

Explanation

The modulated or total power carried by `AM` wave
`P_(T)=P_(C)(1+(m^(2))/(2))`. If `R` is load resistance. `I_(m)` is the current when carrier is modulated and `I_(c)` the current when unmodulated, then
`(P_(T))/(P_(C))=(I_(m)^(2)R)/(I_(c)^(2)R)`, `:. I+(m^(2))/(2)=(I_(m)^(2)R)/(I_(c)^(2)R)`
Given `I_(m)=8.93A`, `I_(c)=8A`
`:. m^(2)=2[((8.93)/(8.0))^(2)-1]:. m=0.7`
Therefore, percentage modulation `=70%`