# Current BalanceWSU-Vancouver PHYS 202Goals1) To explore and verify the right-hand rule governing the force on a current-carrying wireimmersed in a magnetic field.2) To determine the force on the wire...

Answered 4 days AfterApr 12, 2022

## Solution

Dr Shweta answered on Apr 16 2022
Solution
Exercise 1: Force versus Length
2. Making a Prediction
a. Draw a free-body diagram of the magnets (including magnet holder) in equili
ium on the balance with no cu
ent flowing through the circuit. Nva
Solution: when no cu
ent is flowing:
At equili
ium, N=Mg
Where, M = mass of the magnets
N = Normal force exerted on the magnets by the balanceMg
. Draw another free-body diagram of the magnets (including magnet holder) in equili
ium when cu
ent is present in the wire that is between the poles of the magnet. You must apply the right-hand rule in conjunction with the magnetic force equation given earlier to determine the direction of the magnetic force on the wire. Then use Newton’s 3rd Law to determine the force on the magnets. Make sure that your diagram and explanation are very clear here. [Remember that the magnetic field by convention points from the N pole to the S pole outside the magnet itself. Also recall that cu
ent flows out of the red (+) terminal of the power supply and into the black (-) terminal.]
Solution:
Here, l = total length of the wire,
= Force is upward if the cu
ent flowing in the loop is clockwise
Thus, we get two cases:
Case I = cu
ent is clockwise = force on the wire is upward
Case II = cu
ent is anticlockwise = force on the wire is downward
Now, using Newton’s third law which states every action has equal and opposite reaction
Thus, we get two cases:
Case I = force on the magnet is downward
Case II = force on the wire is upward
With magnitude F =IBlN
Thu, Case I = Case II =F
N
Mg
F
Mg
c. On the basis of your free-body diagrams predict whether the electronic balance will read a positive value or a negative value.
Solution: Since, the magnet is initially balanced,
Thus, Case I = Extra downward force = positive value on the balance
Case II = Extra upward force = negative value on the balance
3. Doing the Experiment
d. Record the balance readings for sf37 to sf42 keeping the cu
ent set at 2 A.
Solution:
Trial
SF
Mass(g)
Mass(kg)
Volt
Ampere
check
37
0.21
0.00021
0.3
1.95
1
40
0.14
0.00014
0.4
1.98
2
37
0.24
0.00024
0.3
1.99
3
38
0.42
0.00042
0.4
1.98
4
39
0.35
0.00035
0.3
1.98
5
41
0.7
0.0007
0.4
1.98
6
42
0.96
0.00096
0.4
1.97
6 reversed
42
-0.96
-0.00096
0.4
1.97
e. For sf42 only, reverse the direction of the cu
ent by switching the connections to the black and red terminals on the power supply. What happens to the reading given by the...
SOLUTION.PDF