HELPPP WILL MARK BRAINIEST 18. An incident light beam strikes the edge of its medium at an angle of 42°. The beam refracts at an angle of
90?. Now you know that
a. The critical angle of the medium is 42?.
b. If you decrease the incident angle, the refracted beam will exit the medium.
c. If you increase the incident angle, the refracted beam will not exit the medium
d all of the above

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

its lower due to the doppler effect.: apex