A long straight wire of radius a carries a steady current I. The current is uniformly distributed over its cross-section. The ratio of the magnetic field B and B’ at radial distances a/2 and 2a […]
A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the centre of the loop is B. It is then bent into a circular coil […]
A bar magnet with magnetic moment 2.5×10³ JT⁻¹ is rotating in horizontal plane in the space containing magnetic induction B=4×10⁻⁵ T. The work done in rotating the magnet slowly from a direction parallel to the […]
A thermocouple is made from two metals, antimony and bismuth. If one junction on the couple is kept hot and the other is kept cold then, an electric current will
Options
(a) flow […]
In producing chlorine through electrolysis 100 watt power at 1125 V is being consumed. How much chlorine per minute is liberated? E.C.E. of chlorine is 0.367×10⁻⁶kg/coulomb
Options
(a) 13.6 mg (b) 17.6 mg […]
“On flowing current in a conducting wire the magnetic field is produced around it”. It is a law given by
Options
(a) Lenz (b) Ampere (c) Ohm (d) Maxwell
Correct Answer:
Ampere
Explanation: […]
If a magnetic substance is kept in a magnetic field, then which of the following is thrown out
Options
(a) paramagnetic (b) ferromagnetic (c) diamagnetic (d) antiferromagnetic
Correct Answer:
diamagnetic
Explanation:
No explanation […]
An electric current passes through a long straight wire. At a distance 5 cm from the wire, the magnetic field is B. The field at 20 cm from the wire would be
Options
A wire of length 1 m is placed in a uniform magnetic field of 1.5 tesla at an angle of 30° to it. The current in the wire is 10 amp. Then the force on […]
The magnetic susceptibility of a material of a rod is 449. Permeability of vaccum is 4 π x 10⁻⁷ henry/m. Absolute permeablity of the material of the rod in henry/meter is
Options
(a) […]
2017 Copyright Doctor Dreams Training Academy