Deflection Magnetometer Experiment Questions and Answers for Viva

Answer-1: A deflection magnetometer is an instrument used to measure the magnetic moment of a magnet or the horizontal component of the Earth's magnetic field.

Answer-2: It works on the principle of the interaction between the magnetic field produced by a magnet and the Earth's magnetic field. The deflection of a magnetic needle or a suspended magnet is observed, which is proportional to the magnetic field being measured.

Answer-3: The main components typically include a magnetic needle or a magnet suspended by a thread, a graduated scale, a mirror attached to the needle or magnet, and a telescope for observing the deflection angle.

Answer-4: The principle is based on the torque experienced by the magnetic needle or magnet due to the interaction between the magnetic field being measured and the Earth's magnetic field, causing the needle or magnet to align itself along the magnetic field lines.

Answer-5: Factors such as the strength of the magnetic field, the magnetic moment of the magnet, the distance between the magnet and the needle, and any surrounding magnetic materials can affect the deflection angle.

Answer-6: The sensitivity is defined as the change in deflection angle per unit change in the magnetic field strength.

Answer-7: In the method of vibrations, the magnet is set into oscillations about its equilibrium position, and the time period of oscillation is measured. From the time period, the moment of inertia of the magnet and the restoring torque can be calculated, which allows for the determination of the magnetic moment.

Answer-8: In the null deflection method, the magnetic field produced by the magnet is adjusted until the deflection of the needle or magnet becomes zero. This is achieved by either varying the distance between the magnet and the needle or by using auxiliary magnets to neutralize the Earth's magnetic field.

Answer-9: Advantages include its simplicity, accuracy, and the ability to measure small magnetic fields with high sensitivity.

Answer-10: Limitations include its susceptibility to external magnetic interference, the need for precise calibration, and the requirement for a stable mounting platform.

Answer-11: Improving the sensitivity can be achieved by increasing the length of the magnet's moment arm, reducing friction in the suspension system, and minimizing external disturbances.

Answer-12: Applications include measuring the magnetic moments of permanent magnets, studying the magnetic properties of materials, and geophysical surveys to map variations in the Earth's magnetic field.

Answer-13: The mirror allows for precise measurement of the deflection angle using a telescope or a scale, enhancing the accuracy of the measurement.

Answer-14: Temperature changes can affect the magnetic properties of the materials used in the magnetometer, as well as the suspension system, leading to variations in the measurements.

Answer-15: A practical setup typically includes a stable base, a graduated scale or protractor, a magnetic needle or magnet suspended by a torsion fiber, a mirror attached to the needle or magnet, and a telescope or a magnifying glass for reading the deflection angle.

Answer-16: A tangent galvanometer measures electric currents using the Earth's magnetic field, while a deflection magnetometer measures magnetic fields directly.

Answer-17: The accuracy can be verified by comparing the measurements obtained with known magnetic fields or by conducting calibration tests using standard magnets.

Answer-18: The Earth's magnetic field exerts a torque on the magnetic needle or magnet, causing it to align itself along the magnetic field lines and thus affecting the deflection angle.

Answer-19: Safety precautions may include handling magnets carefully to avoid injury, ensuring proper insulation of electrical connections, and avoiding exposure to strong magnetic fields that could interfere with the measurements.