Electricity and Magnetism Answers

A 20 m constantan wire with 4 mm thickness connected to a 6 V battery. Given 

resistivity of constantan is 49  10-8  m. Calculate

a. Current in the circuit

b. Power dissipated by the wire

A parallel plate air capacitor has a capacitance of 5.0 F. (a) What is its capacitance if the separation between the plates is decreased to one-half its original value while keeping all other factors constant? (b) What is its capacitance if the area of the plates is decreased to one-half its origi alue while keeping all other factors constant? (c) What is the capacitance if a dielectric of relative permeability of 2 is inserted between the plates of the original air capacitor?

A proton is released from rest in a uniform horizontal electric field. It travels 3.25 m for 5 μs. Find the acceleration of the proton and the magnitude of the electric field.

What is the total electric flux through a closed surface containing a 2.0 μC charge?

Spheres A, B, and C have charges +8.0 C, +12.0 C, and -5.0 C, respectively. Spheres A and B touched each other and then separated. Sphere A then touched sphere C and then separated. (a) What is the total charge on the three spheres before and after touching each other? (b) What is the final charge on each sphere assuming they are identical? (c) What is the final charge on each sphere assuming that r_A=r_B=2r_C?

A wire of length 0.050 𝑚 and carries a current 𝐼 is in a horizontal uniform magnetic field B of

2.50 𝑇 which is perpendicular to the rod. The weight of the wire is 0.80 𝑁. What is the value

of the current 𝐼 if the magnetic force on the wire equals its weight?

A flat circular coil which has 𝑁 turns each of diameter d carries a current 𝐼. If 𝜇0 is the

permeability of free space, what is the expression of magnetic field 𝐵 at the center of the

coil?

  A current-carrying circular plate with A= 32.2 m2 is inclined at 34° with the Earth’s field direction. If the magnitude of the magnetic field is 48 125 nT, solve for the (a) angle between the normal to the surface and the B vector, and the (b) magnetic flux through the antenna

 Solve for the magnetic flux through a loop with an area of 8.5 ✕ 10 -4 m2 found perpendicular to a magnetic field with magnitude 0.75 T.

An 88.30-cm wire that carries an electric current of 1.35 A perpendicular to the field has experienced a magnetic force of 9.0✕10 -3 N. Solve for the magnitude of the magnetic field that caused this force.