A conducting rod of 1m length and 1 kg mass is suspended by two vertic...
A conducting rod of 1m length and 1 kg mass is suspended by two vertic...
The Situation:
A conducting rod of 1m length and 1 kg mass is suspended by two vertical wires through its ends. An external magnetic field of 2 T is applied normal to the rod. The task is to determine the current that needs to be passed through the rod in order to make the tension in the wires zero.
Solution:
To solve this problem, we can use the principles of electromagnetism and equilibrium.
Step 1: Analyzing the Forces:
When a current-carrying conductor is placed in a magnetic field, a force is exerted on the conductor due to the interaction between the magnetic field and the current. This force is given by the equation F = BIL, where F is the force, B is the magnetic field strength, I is the current, and L is the length of the conductor.
In this case, since the rod is suspended by two vertical wires, there are two forces acting on the rod due to the magnetic field. These forces are in opposite directions and are equal in magnitude.
Step 2: Finding the Tension:
The tension in the wires can be calculated by considering the equilibrium of forces acting on the rod. In this case, the forces acting on the rod include the weight of the rod and the forces due to the magnetic field.
Since the tension in the wires needs to be zero, the sum of the forces due to the magnetic field should cancel out the weight of the rod.
Step 3: Equating Forces:
The weight of the rod can be calculated using the equation W = mg, where W is the weight, m is the mass, and g is the acceleration due to gravity.
The force due to the magnetic field can be calculated using the equation F = BIL.
Setting these two forces equal to each other, we get:
W = F = BIL
Substituting the values, we have:
mg = BIL
Simplifying the equation, we get:
I = mg / (BL)
Step 4: Calculating the Current:
Substituting the given values, we have:
I = (1 kg * 9.8 m/s^2) / (2 T * 1 m)
Simplifying, we find:
I = 4.9 A
Therefore, the current that needs to be passed through the rod in order to make the tension in the wires zero is 4.9 A, which is closest to option (c) 5 A.
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