MCQ
A cell is connected between two points of a uniformly thick circular conductor. The magnetic field at the centre of the loop will be $($Here $i_1$ and $i_2$ are the currents flowing in the two parts of the circular conductor of radius $'a\ ’$ and $\mu_0$ has the usual meaning$)$
  • Zero
  • B
    $\frac{\mu_0}{2 a}\left(i_1-i_2\right)$
  • C
    $\frac{\mu_0}{2 a}\left(i_1+i_2\right)$
  • D
    ${\frac{\mu_0}{a}}\left(i_1+i_2\right)$

Answer

Correct option: A.
Zero
Zero  

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

Which among the following is false?
A potentiometer consists of a wire of length 4 m and resistance 10Ω. It is connected to a cell of e.m.f. 2 V. The potential difference per unit length of the wire will be(a) 0.5 V/m(b)  2 V/m(c)  5 V/m(d) 10 V/m
       
An atomic power nuclear reactor can deliver $300\ MW.$ The energy released due to fission of each nucleus of uranium atom $U^{238}$  is $170\ MeV.$ The number of uranium atoms fissioned per hour will be
If a resistance $R_2$ is connected in parallel with the resistance $R$ in the circuit shown, then possible value of current through $R$ and the possible value of  $R_2$ will be
The photoelectrons emitted from a metal surface are such that their velocity:
Three observers $A, B$ and $C$ measure the speed of light coming from a source to be $v_A, v_B$ and $v_C$. The observer $A$ moves towards the source, the observer $C$ moves away from the source with the same speed. The observer $B$ stays stationary. the surrounding space is vacuum every where. Then
A combination of two thin lenses with focal lengths $\mathrm{f}_1$ and $\mathrm{f}_2$ respectively forms an image of distant object at distance $60 \ cm$ when lenses are in contact. The position of this image shifts by $30 \ cm$ towards the combination when two lenses are separated by $10 \ cm.$ The corresponding values of $\mathrm{f}_1$ and $\mathrm{f}_2$ are
Electromagnets are made of soft iron because soft iron has:
  1. High retentivity and high coercive force.
  2. High retentivity and low coercive force.
  3. Low retentivity and high coercive force.
  4. Low retentivity and low coercive force.
The energy of a hydrogen atom in its ground state is -13.6eV. The energy of the level corresponding to the quantum number n = 2 (first excited state) in the hydrogen atom is(a) – 2.72 eV(b) – 0.85 eV(c) – 0.54 eV(d) – 3.4 eV
       
The number of turns in the coil of an ac­ generator is $5000$ and the area of the coil is $0.25m^2.$ The coil is rotated at the rate of $100$ cycles/sec in a magnetic field of $0.2W/m^2.$ The peak value of the $emf$ generated is nearly