Question

a) Two long straight wires are carrying current out of the page and into the page as shown Draw the direction of the force exerted on wire 2. X 1 b) A rectangular loop of wire with current flowing through it is sitting in an external magnetic field as shown below (the magnetic field in the dashed region is caused by magnets that are not shown in the diagram). What direction will the loop rotate? Answer by saying which side of the loop will move out of the page and which side of the loop will move into the page. c) An electron and a proton are traveling the towards a region of constant magnetic field. Once the charges enter the magnetic field, one curves to the left and one curves to the right. BO Label which path is the electron and which path is the proton. Which particle is traveling faster, how do you know? d) A short solenoid with current flowing through it is placed near a permanent magnet. S N Current is traveling up on side of the coll facing you Will the magnet be attracted or repelled from the solenoid?

Answer 1

(a) Let,
B
₁ be the ,agnetic field created by wire 1, and,
F
₂₁ be the force on wire 2 exterted by wire 1.

We know,
F
₂₁ = I₂ (
L
₂ x
B
₁ ), where,
L
₂ is the length of wire 2, directed towards the current I₂.

Hence, the force on wire 2 by wire 1 is shown below :

BA 21 NT) Iz I

(c) The particle that curves to the left is electron,

and, the particle that curves to the right is proton.

B Electron's path Proton's path -

The electron is travelling faster, because mass of an electron is about 1800 times less than that of a proton, so, though both of them experience same amount of magnetic force, the acceleration of the electron will be higher than that of the proton.