To determine the resistance of the ammeter when a galvanometer is shunted with a resistance, we need to calculate the parallel combination of the galvanometer resistance and the shunt resistance.
A galvanometer can be converted into an ammeter by connecting a shunt resistance (in parallel with the galvanometer). The combined resistance \(R_A\) of the ammeter is given by the formula for parallel resistances:
\(R_A = \frac{R_g \cdot R_s}{R_g + R_s}\)
where:
- \(R_g\) is the resistance of the galvanometer = \(520 \, \Omega\)
- \(R_s\) is the shunt resistance = \(20 \, \Omega\)
Substituting the values into the formula, we get:
\(R_A = \frac{520 \cdot 20}{520 + 20}\)
\(R_A = \frac{10400}{540}\)
Upon calculating, we have:
\(R_A = 19.259 \, \Omega\)
Rounding this result, we get an effective resistance of approximately \(19.3 \, \Omega\).
Thus, the resistance of the ammeter is \(19.3 \, \Omega\). This correctly matches with the given option.
Important Questions from Moving Charge and Magnetism
A square loop with each side 1 cm, carrying a current of 10 A, is placed in a magnetic field of 0.2 T. The direction of magnetic field is parallel to the plane of the loop. The torque experienced by the loop is:
A long straight wire of circular cross-section with radius ' a ' carries a steady current ' I ' which is uniformly distributed across the cross-section. The magnetic field in the region r < a and r > a is represented by:
A 300-turn rectangular coil of length 20cm and breadth 12cm carries a current of 12A in a magnetic field of 6T. The plane of the coil makes an angle of 60∘ with the magnetic field. What is the torque acting on the coil?
An alpha-particle moves with a speed of 5×105m/s. It enters a region where there is a magnetic field of magnitude 4 T, directed at an angle of 45° to the X-axis and lying in the XY plane. The magnitude of the magnetic force on the alpha-particle is:
An electron moves around the nucleus in a hydrogen atom of radius 0.05nm with a velocity of 2×106m/s. The magnetic field produced at the center of the nucleus is:
