Question

Two similar coils are kept mutually perpendicular such that their centres coincide. At the centre, find the ratio of the magnetic field due to one coil and the resultant magnetic field by both coils, if the same current is  flown

(a) 1:  

(b) 1 : 2

(c) 2 : 1

(d)  

Answer

(a) 1:  

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A current passes through a wire of non-uniform cross-section. Which of the following quantities are independent of the cross-section?
  1. The charge crossing in a given time interval.
  2. Drift speed.
  3. Current density.
  4. Free-electron density.

There are  n similar conductors each of resistance R. The resultant resistance comes out to be  x when connected in parallel. If they are connected in series, the resistance comes out to be

(a)   

(b)  

(c) x/n     

(d) nx

The ground state energy of hydrogen atom is -13.6 eV. The kinetic and potential energies of the electron in this state are:

Spherical aberration in a lens

(a) Is minimum when most of the deviation is at the first surface

(b) Is minimum when most of the deviation is at the second surface

(c) Is minimum when the total deviation is equally distributed over the two surface

(d) Does not depend on the above consideration

Two concave lenses L1 and L2 are kept in contact with each other. If the space between the two lenses is filled with a material of refractive index $\mu\approx1,$ the magnitude of the focal length of the combination:
  1. Becomes undefined.
  2. Remains unchanged.
  3. Increases.
  4. Decreases.
The net resistance of an ammeter should be small to ensure that:
  1. It does not get overheated.
  2. It does not draw excessive current.
  3. It can measure large currents.
  4. It does not appreciably change the current to be measured.
An electric dipole is placed in a uniform electric field. The net electric force on the dipole.
  1. Is always zero.
  2. Depends on the orientation of the dipole.
  3. Can never be zero.
  4. Depends on the strength of the dipole.

Assertion   :  The resistance of super-conductor is zero.

Reason      : The super-conductors are used for the transmission of electric power.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

A long, straight wire carries a current i. The magnetizing field intensity H is measured at a point P close to the wire. A long, cylindrical iron rod is brought close to the wire so that the point P is at the centre the rod. The value of H at P will:
  1. Increase many times.
  2. Decrease many times
  3. Remain almost constant.
  4. Become zero.

Electromagnetic radiation of highest frequency is

(a) Infrared radiations

(b) Visible radiation

(c) Radio waves

(d) g-rays