Galvanometer constant of tangent galvanometer depends upon earths magnetic field.

Collegedunia Team logo

Collegedunia Team

Content Curator

Tangent galvanometer is an instrument used to measure the small currents in a circuit. The instrument consists of a circular coil of wire, usually made of copper, mounted on a horizontal axis. The coil is suspended between the poles of a permanent magnet, which creates a uniform magnetic field inside the coil. A thin, light magnetic needle is suspended at the center of the coil, parallel to the plane of the coil. The needle is free to rotate about a vertical axis, and it aligns itself with the magnetic field.

The principle of the tangent galvanometer is based on the fact that when a current-carrying wire is placed in a magnetic field, a force is exerted on the wire. The magnitude of this force depends on the strength of the magnetic field, the length of the wire, and the current passing through the wire. The direction of the force is perpendicular to both the magnetic field and the direction of the current.

The galvanometer constant of a tangent galvanometer is defined as the ratio of the magnetic field strength to the current required to produce a deflection of one tangent division on the scale. It is denoted by the symbol G.

G = B/I

B is the magnetic field strength; I is current required to produce deflection of one tangent division on scale

The galvanometer constant of a tangent galvanometer depends on the strength of the earth's magnetic field. The earth's magnetic field is not uniform, and its strength varies from place to place. The galvanometer constant of a tangent galvanometer is maximum when it is aligned with the direction of the earth's magnetic field. This is because the maximum force is exerted on the wire when it is perpendicular to the magnetic field, and the force is directly proportional to the magnetic field strength.

If the tangent galvanometer is not aligned with the direction of the earth's magnetic field, the galvanometer constant will be smaller. This is because the force exerted on the wire is not perpendicular to the magnetic field, and only the component of the force perpendicular to the field contributes to the deflection of the needle.

Therefore, to obtain accurate readings with a tangent galvanometer, it is necessary to align it with the direction of the earth's magnetic field. This can be done by using a compass or a declination instrument. The galvanometer constant can also be determined experimentally by measuring the deflection of the needle for different values of the current and the magnetic field strength, and then calculating the ratio B/I.

Also check:

CBSE CLASS XII Related Questions

  • 1.
    Draw the plot of potential energy of a pair of nucleons as a function of their separation. Write two important conclusions that can be drawn from this plot.


      • 2.
        Consider the nuclear reaction \( X \to Y + Z \). Let \( M_x \), \( M_y \), and \( M_z \) be the masses of the three nuclei X, Y, and Z respectively. Then which of the following relations hold true?

          • \( (M_x - M_z)<M_y \)
          • \( (M_x - M_y)<M_z \)
          • \( M_x>(M_y + M_z) \)
          • \( M_x<(M_y + M_z) \)

        • 3.

          (I) The real image of an object placed between $f$ and $2f$ from a convex lens can be seen on a screen placed at the image location. If the screen is removed, is the image still there? Explain.

          (II) Plane and convex mirrors produce virtual images of objects. Can they produce real images under some circumstances? Explain.


            • 4.

              A parallel beam of monochromatic light falls normally on a single slit of width $a$ and a diffraction pattern is observed on a screen placed at distance $D$ from the slit. Explain:

              (I) the formation of maxima and minima in the diffraction pattern, and

              (II) why the maxima go on becoming weaker and weaker with its increasing number $n$.


                • 5.

                  A square loop of side 0.50 m is placed in a uniform magnetic field of 0.4 T perpendicular to the plane of the loop. The loop is rotated through an angle of $60^\circ$ in 0.2 s. The value of emf induced in the loop will be:

                    • 5 V
                    • 3.5 V
                    • 2.5 V
                    • Zero V

                  • 6.
                    A wire of length \(L\) is bent round into (i) a square coil having \(N\) turns and (ii) a circular coil having \(N\) turns. The coil in both cases is free to turn about a vertical axis coinciding with the plane of the coil, in a uniform, horizontal magnetic field and carry the same currents. Find the ratio of the maximum value of the torque acting on the square coil to that on the circular coil.

                      CBSE CLASS XII Previous Year Papers

                      Comments


                      No Comments To Show