Does the slope of the interest yield curve typically have a substantial impact on a bank’s net
interest margin? 

No, it doesn’t, since the slope of the yield cure is unrelated to the spread between short-term and long-term interest rates. 

No, it doesn’t. There isn’t any link at all between the slope of the interest yield curve and a bank’s net interest margin. 

Yes it does. In banking, long-term rates usually apply to bank deposits and money market borrowings whereas short-term interest rates are attached to loans and securities.   

Yes it does. Long-term rates usually apply to a bank’s assets (loans, securities, etc.) and the short term interest rates are generally attached to liabilities (deposits, money market borrowings, etc.).