The electron beam emerging from a certain high-energy electron accelerator has a circular cross section of radius 1.00 mm. The beam current is 8.00 μA. Find the current density in the beam assuming it is uniform throughout.

What is the current in a wire of radius R = 2.83 mm if the magnitude of the current density is given by (a) J, - Jor/R and (b) J, = Jo(1-r/R) in which r is the radial distance and Jo = 7.58 x 104 A/m2? (c) Which function maximizes the current density near the wire's surface? (a) Number i Units (b) Number i Units (c)

What is the current in a wire of radius R = 2.01 mm if the magnitude of the current density is given by (a) Ja = Jor/R and (b) Jb = Jo(1 - r/R) in which ris the radial distance and Jo = 6.22 x 104 A/m2? (c) Which function maximizes the current density near the wire's surface? (a) Number Units (b) Number Units (c)

A beam contains 2.7 x 109 doubly charged positive ions per cubic centimeter, all of which are moving north with a speed of 4.9 × 105 m/s. What is (a) the magnitude of the current density and (b) direction of the current density . (c) What additional quantity do you need to calculate the total current i in this ion beam? (a) Number Units A/m^2 to the north (b) cross-sectional area of ion beam (c) Use correct number of significant digits; the tolerance is +/-1 in the 2nd significant digit

The vector current density of a 3m long and 3mm diameter conductor is given as 155630 A/m^2. Determine the curent on the conductor, its free electron density, the drift velocity of the charges and the number of electrons passing through the conductor for 3 seconds.

Wires A and B, having equal lengths of 41.8 m and equal diameters of 2.89 mm, are connected in series. A potential difference of 61.6 V is applied between the ends of the composite wire. The resistances are RA = 0.108 0 and Rg - 0.617 0. For wire A, what are (a) magnitude Jof the current density and (b) potential difference V? (c) Of what type material is wire A made (see the table below)? For wire B. what are (d) Jand (e) V? (f) Of what type material is B made? Resistivities of Some Materials at Room Temperature (20°C) Resistivity, p (N-m) Temperature Coefficient of Resistivity, a (K) Material Typical Metals 4.1 x 10- 1.62 x 10- 1.69 x 10- Silver 4.3 x 10- Copper Gold 4.0 x 10- 4.4 x 10- 0.002 x 10- 45 x 10- 6.5 x 10- 2.35 x 10 2.75 x 10- 4.82 x 10- 5.25 x 10- 9.68 x 10- 10.6 x 10- Aluminum Manganin Tungsten Iron Platinum 3.9 x 10- Typical Semiconductors 25 x 10 8,7 x 10- -70 x 10- Silicon, pure Silicon, n-type Silicon, p-type 2.8 x 10- Typical Insulators 10- 104 ~10M Glass Fused…