Physics Test 12...

A & B are two concentric circular conductors of centre O and carrying currents i₁ & i₂ as shown in the diagram. If ratio of their radii is 1:2 and ratio of the flux densities at O due to A and B is 1:3, then the value of i₁ & i₂ will

Domain formation is the necessary feature of

A magnet 10 cm long and having a pole strength 2 A-m is deflected through 30º from the magnetic meridian. The horizontal component of earth’s induction is  0.32 x 10 ^-4T then the value of deflecting couple is

A spectrum of iron of permeability 8 x 10 ^-3 Wb / A-m  is placed in a magnetic field of strength 160 A/m. Then magnetic induction in this iron is

Two magnets each of magnetic moment M are placed so as to form a cross at right angles to each other. The magnetic moment of the system will be

At a certain place, the horizontal component of earth’s magnetic field is √3 times of its vertical component, the angle of dip at that place is

The work done in turning a magnet of magnetic moment M by an angle of 90º from the meridian is n times the corresponding work done to turn it through an angle of 60º. The value of n is given by

The time of vibration of a dip needle vibrating in the vertical plane in the magnetic meridian is 3s.When the same magnetic needle is made to vibrate in the horizontal plane, the time is vibration is again 3s. Then angle of dip will be

A magnet makes 30 oscillations per minute in the earth’s magnetic field. If the magnetic field is doubled. The period of oscillation of magnet is

A moving conductor coil produces an induced emf. This is in accordance with