What is the modulation index of an FM phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency if the highest modulating frequency is 1000 Hz?

Explication

Divide the peak deviation by the modulating frequency: 3000 Hz ÷ 1000 Hz = 3, the deviation being quoted as the swing to either side of the carrier and so already the peak value. Note the internal inconsistency: the quantities supplied — maximum deviation and highest modulating frequency — are precisely what the same pool defines as deviation ratio in E8B05 and E8B09, yet this question calls the result a modulation index; the arithmetic and the keyed answer are unaffected.