When the market interest rate is equal to the coupon interest rate, bonds sell at their par value.

When the market interest rate is below the coupon interest rate, bonds sell above their par value. 

When the market interest rate exceeds the coupon interest rate, bonds sell below their par value.

There is an inverse relationship between value of bonds and market interest rates

Bonds with longer maturity have a higher sensitivity to changes in market  have lower interest rate risk.