Parallel Wires: Two long parallel wires are placed side-by-side on a horizontal table and carry current in the same direction. The current in one wire is 20 A, and the current in the other wire is 5 A. If the magnetic force on the 20-A wire has magnitude F, what is the magnitude of the magnetic force on the 5-A wire? No external magnetic fields are present.
A. 4F
B. 2F
C. F
D. F/2
E. F/4
Answer: C
You might also like to view...
Calculate the rate of heat transfer between a 15-cm-OD pipe at 120°C and a 10-cm-OD pipe at 40°C. The two pipes are 330-m-long and are buried in sand [k = 0.33 W/(m K)] 12 m below the surface (Ts = 25°C). The pipes are parallel and are separated by 23 cm (center to center) distance.
GIVEN
Two parallel pipes buried in sand
Pipe 1
Outside diameter (D1) = 15 cm = 0.15 m
Temperature (T1) = 120°C
Pipe 2
Outside diameter (D2) = 10 cm = 0.1 m
Temperature (T2) = 40°C
Length of pipes (L) = 330 m
Thermal conductivity of the sand (k) = 0.33 W/(m K)
Depth below surface (d) = 1.2 m
Surface temperature (Ts) = 25°C
Center to center distance between pipes (s) = 23 cm = 0.23 m
FIND
The rate of heat transfer between the pipes (q)
ASSUMPTIONS
The thermal conductivity of the sand is uniform
Two dimensional, steady state heat transfer
The motion of a particle is described in the velocity versus time graph shown in the figure. We can say that its speed
A) increases. B) decreases. C) increases and then decreases. D) decreases and then increases.
Who was the first to successfully explain the photoelectric effect?
a. Planck b. Young c. Bohr d. Einstein
A light ray is incident on the surface of water (n = 1.33) at an angle of 60° relative to the normal to the surface. The angle of the reflected wave is
A. 80°. B. 40°. C. 20°. D. 60°. E. 30°.