An electric dipole of dipole moment p is aligned parallel to a uniform electric field E. The energy required to rotate the dipole by 90^o is

Two rods are joined end to end, as shown. Both have a cross-sectional area of 0.01 cm². Each is 1 meter long. One rod is of copper with a resistivity of 1.7 $$ \times $$ 10^$$-$$6 ohm-centimeter, the other is of iron with a resistivity of 10^$$-$$5 ohm-centimeter.

How much voltage is required to produce a current of 1 ampere in the rods?

A 12 cm wire is given a shape of a right angled triangle ABC having sides 3 cm, 4 cm and 5 cm as shown in the figure. The resistance between two ends (AB, BC, CA) of the respective sides are measuread one by one ratio

A long straight wire carries a certain current and produces a magnetic field 2 $$ \times $$ 10^$$-$$4 Wb m^$$-$$2 at a perpendicular distance of 5 cm from the wire. An electron situated at 5 cm from the wire moves with a velocity 10⁷ m/s towards the wire along perpendicular to it. The force experienced by the electron will be (charge on electron 1.6 $$ \times $$ 10^$$-$$19 C)