1)A coil of length 1cm has N turns and carries an electric current I. It creates at a point M a magnetic field of intensity B.
-If a current 3I is sent in the coil the field strength at M becomes:
a. 3B b. B/3 c. B
-If the number of turns per unit length is doubled the field strength at M becomes:
a. 2B b. B/2 c. B
2)If the coil of the preceding exercise the core of relative permeability is equal to 1 is replaced by another core of relative permeability=10 ,the field strength at M becomes:
a. 10B b. B/10 c. B
IF THERE'S ANYTHING TO CALCULATE OR EXPLAIN PLEASE SHOW YOUR WORK
THANKS IN ADVANCE.