Home
Class 12
PHYSICS
A straight horizontal conducting rod of ...

A straight horizontal conducting rod of length `l` and mass `m` is suspended by two vertical wires at its ends. A current I is set up in the rod through the wires.
(i) What magnetic field should be set up normal to the conductor in order that the tension in the wires is zero.
(ii) What will be the total tension in the wires if the direction of current is reversed, keeping the magnetic field same as before?

Text Solution

Verified by Experts

(i) Tension in the supporting wires will be zero if the weight of the rod acting vertically downwards is balanced by the upward force on rod due to magnetic field, i.e.,
`mg=IlB` or `B=(mg)/(Il)`
(ii) If the direction of current is reversed, the magnetic force on rod will act in the vertical downward direction. Now total tension in the wires will be
`T=mg+IlB=mg+mg=2mg=2IlB`
Promotional Banner

Topper's Solved these Questions

  • MAGNETIC EFFECT OF CURRENT AND MAGNETISM

    PRADEEP|Exercise Conceptual Problems (d)|2 Videos

  • MAGNETIC EFFECT OF CURRENT AND MAGNETISM

    PRADEEP|Exercise Very Short Answer Questions (a)|2 Videos

  • ELECTROSTATICS

    PRADEEP|Exercise ASSERTION-REASON TYPE QUESTIONS|2 Videos

  • OPTICS

    PRADEEP|Exercise Multiple choice questions|1 Videos

Similar Questions

Explore conceptually related problems

A straight horizontal conducting rod of length 0*45m and mass 60g is suspended by two vertical wires at its end. A current of 5*0A is set up in the rod through the wires. (a) What magnetic field should be set up normal to the conductor in order that the tension in the wires is zero? (b) What will be the total tension in the wires if the direction of current is reversed, keeping the magnetic field same as before. (Ignore the mass of the wire) g=9*8ms^-2 .

A straight horizontal conducting rod of length 0*60m and mass of 60g is suspended by two vertical wires at its ends. A current of 5*0A is set up in the rod through the wire. (a) What magnetic field should be set up normal to the conductor in order that the tension in the wire is zero? (b) What will be total tension in the wires if the direction of current is reversed, keeping the magnetic field same as before (Ignore mass of the wire), g=10ms^-2 .

A conducting rod of 1 m length and 1 kg mass is suspended by two verticle wires through its ends. An external magnetic field of 2T is applied normal to the rod. Now the current to be passed through the rod so as to make the tension in the wire zero is [Take g = 10 ms^(-2)]

An iron rod of mass 50 g and length 50 cm is suspended by master wires as shown in the figure. Calculate the magnitude and direction of magnetic field to be set in the region such that the tension is the wires is zero. The current in the rod is 4 A.

The magnetic field in a straight current carrying conductor wire is: