What is the difference between the b field and the h field?

According to the tide table below what time of day will the highest tide occur?

Avery long solenoid of inner radius 2.75 cm creates an oscillating magnetic field of the form = for this solenoid, =0.00425 t and =319 rad/s. (a)what is the maximum value of the induced electric field at a perpendicular distance 1.45 cm from the axis of the solenoid? (b) what is the maximum value of the inducted electric field at a point 5.85 cm perpendicular from the axis of the solenoid?

Considering only the earth's rotation, determine how much later the asteroid would have had to arrive to put the explosion above helsinki at longitude 25˚ e? this would have obliterated the city.