Figure shows a part of an electric circuit. The wires AB, CD, and EF are long and have identical resistances. The separation between the neighbouring wires is 1.0 cm. The wires AE and BF have negligible resistances and the ammeter reads 30 A . Calculate the magnetic force per unit length of AB and CD. `

Figure shows a part of an electric circuit. ABCD is a rectangular loop made of uniform wire. The length AD= BC = 1 cm. The sides AB and DC are long as compared to the other two sides. Find the magnetic force per unit length acting on the wire DC due to the wire AB if the ammeter reads 10A.

The two long, straight wires carrying electric currents of 10A each in opposite directions. The separation between the wires is 5.0 cm. Find the magnetic field at a point P midway between the wires.

Three coplanar parallel wires, each carrying a current of 10 A along the same direction, are placed with a separation 5.0 cm between the consecutive ones. Find the magnitude of the magnetic force per unit length acting on the wires.

Shows a conducting square loop placed parallel to the pole faces of a ring magnet. The pole faces have an area of 1cm^2 each and the field between the poles is 0.10 T. The wires making the loop are all outside the magnetic field. If the magnet is removed in 1.0 s, what is the average emf induced in the loop?

Calculate the resistivity of a material of a wire 10 m long. 0.4 mm in diameter and having a resistance of 2.0Omega .

Figure shows a 2.0 V potentiometer used for the determination of internal resistance of a 1.5 V cell. The balance point of the cell in open circuit is 76.3 cm. When a resistor of 9.5 Omega is used in the external circuit of the cell, the balance point shifts to 64.8 cm length of the potentiometer wire. Determine the internal resistance of the cell

Two long wires a and b, carrying equal currents of 10*0A, are placed parallel to each other with a separation of 4*00 cm between them as shown in figure. Find the magnetic field B at each of the points P,Q and R.

Calculate the force per unit length on a long straight wire carrying current of 4A due to a parallel wire carrying 6 A current if the distance between the wire is 3cm .

Shows a smooth pair of thick metallic rails connected across a battery of emf epsilon having a negligible internal resistance. A wire ab of length l and resistance r can slide smoothly on the rails. The entire system lien in a horizontal plane and is immersed in a uniform vertical magnetic field B. At an instant t, the wire is given a small velocity v towards right. (a) find the current in it at this instant. What is the direction of the current? (b) What is the force acting on the wire at this instant? (c) Show that after some time the wire ab will slide with a constant velocity. Find this velocity.