Question

1)

Which of the following produces a magnetic field?

a		stationary net charge
b		electric current
c		mass
d		heat

2)

A long copper wire of radius 10cm is laid on the ocean floor connecting an island to the mainland. A small species of shrimp is sensitive to magnetic fields, and it will die if subjected to a field strength greater than 0.004T. What current run through the cable would produce a magnetic field of this strength at its surface?

a		318 A
b		400 A
c		2000 A
d		2.0x105 A
e		4.0x106 A

3)

Select the one of the following that is NOT a virtual image

a		Image seen in a mirror
b		Image seen in a magnifying glass
c		Image seen through curved glass at an aquarium
d		Movie at the theater

Answer 1

1) Moving charge produces Ę' field. since elechris Current is the result from motion of electrons so AM8 is b) electric current 2) f Bods = leo Tene =) Blds = lo fane = B(210) = lo lene - fene 2 ITR X B B = 0.004T leo R = 10 cm 2xn xlox 10 x 0.004 ull x 10-7 - 10x10?m ro a unxio = 2000 A .: Ang e) 2000 A 3) Mirror virtual magnifying glass virtual aquaricem gloss svirkual real image is formed d) Movie at the theater on cinema screen So Ang