two physics questions please help
Question: 3
Consider a point P at a distance R = 10.5 cm on the perpendicular bisector of a straight wire of length 35.0 cm carrying a current of 75.0 mA. Calculate the magnitude of the magnetic field at P due to the current. Hint: use the Biot-Savart law realizing that the length is not very long.
Question: 4
An AC source with a maximum voltage of 120 V and f = 40.0 Hz is connected between points a and b in the figure below. Calculate the rms voltages between the following points.
a) a and b
b) b and c
c) c and d
d) b and d