The torque on a current loop is zero if the angle between the positive normal and the magnetic field is either `theta =0` or `theta = 180^@`. In which of the two orientations, the equilibrim is stable?

If theta is the angle between two vectors vecaandvecb then veca*vecbge0 only when

If theta is the angle between two vectors vec a and vec b , then veca. b ge 0 only when

A circular loop carrying a current a current I has wire of total length L. A uniform magnetic field B exists parallel to the plane of the loop. (a ) find the torque on the loop.(b) If the same length of the wire is used to form a square loop, what would be the torque? Which is larger?

A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A 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 wires.) g = 9.8 ms^2 ?

A rectanguIar coil of length 0.12 m and width 0.1m having 50 turns of wire is suspended vertically in a uniform magnetic field of strength 0.2 (Weber)/m^2 . The coil carries a current of 2A. If the plane of the coil is inclined at an angle of 30degree with the direction of the field, the torque required to keep the coil in stable equilibrium will be

A long straiht telephone cable contains six wires , each carrying a current of 0.5 A. The distance between the wires can be neglected. a. If the current in all six wires are in the same direction, what is the magnitude of the magnetic field 10 cm from the cable ? b. If four wires carry current in one direction and the other two in opposite directions, what is the field magnitude at 10 cm from the cable ?

When a coil of area A is oriented through an angle of orientation (theta=omega t) in a uniform magnetic field B, the induced emf is given by :