How much current must pass through a 400-turn ideal solenoid that is 4.0 cm long to generate a 1.0-T magnetic field at the center? ( μ 0 = 4π × 10 -7 T ∙ m/A)

The earth’s northern magnetic pole acts like

Which of the following statements is true for a series  RLC ac circuit in resonance? (There could be more than one correct choice).

A 1.0-mm diameter extension cord is made of metal having a resistivity of 1.68 × 10 -8 Ω ∙ m. When it carries a current of 15 A, what is the potential difference between two points in the cord that are 50 m apart?

A 4.0-g bead carries a charge of 20 μC. The bead is accelerated from rest through a potential difference  V, and afterward the bead is moving at 2.0 m/s. What is the magnitude of the potential difference  V?

If the result of your calculation of a quantity has SI units kg ∙ m 2/(s 2 ∙ C), that quantity could be

Calculate the Values of the currents I1 and I2 in the circuit shown. Screen Shot 2021-02-27 at 6.58.28 PM.png 

The strength of the gradient over distance, such as 70 mT/m/s, is called    ________________.

Why is helium is the cryogen of choice in superconducting magnets?

Which type of magnetism produces small positive effects to the external magnetic field?