smartpants

"Sooner you recover the money, lesser you are at risk and hence lesser is the duration."

This statement will take care of all the three queries on Duration.

Higher Coupon ----> You'll recover money sooner ----> lesser Risk ---> less duration

Longer maturity ---> You'll get money later ----> higher Risk ---> higher duration

Higher Yield ---> You invested lesser money ---> You'll recover money sooner ----> Lower Risk ---> lower duration