Question 1: Define a magnetic field in your own words.

Answer: A magnetic field is the region around a magnet where magnetic forces can be detected or felt.

Question 2: Explain how the magnetic field lines around a bar magnet are oriented and what they indicate about the magnetic force.

Answer: Magnetic field lines around a bar magnet emerge from the north pole and curve around to enter the south pole, indicating the direction of the magnetic force and showing the strength of the magnetic field.

Question 3: Describe the mechanism by which a magnetic field exerts a force on moving charges.

Answer: A magnetic field exerts a force on moving charges through the Lorentz force, which acts perpendicular to both the velocity of the charge and the magnetic field direction, causing the charges to deflect.

Question 1: A current of 3 A flows through a straight wire that is 2 meters long. If the magnetic field strength at the wire is 0.05 Tesla, calculate the magnetic force acting on the wire. Use the formula F = BIL sinθ, assuming θ = 90°. Show your calculations.

Answer: F = 0.05 T × 3 A × 2 m × sin90° = 0.05 × 3 × 2 × 1 = 0.3 Newtons

Question 2: A magnetic flux of 0.2 Weber passes through a coil with an area of 0.01 m². If the magnetic field is perpendicular to the coil, what is the magnetic flux density (B)? Use the relation Φ = B × A. Show your work.

Answer: B = Φ / A = 0.2 Weber / 0.01 m² = 20 Tesla

Question 1: Describe a simple experiment to demonstrate the presence of a magnetic field around a current-carrying wire. Include the variables involved and safety precautions.

Answer: A common experiment involves passing a current through a straight wire and using a compass placed near the wire. The deflection of the compass needle indicates the magnetic field. Variables include current strength (independent), magnetic field strength (dependent), and distance from wire (controlled). Safety precautions include ensuring the wire is properly insulated, not touching live current sources, and avoiding short circuits.

Question 1: A student measures the magnetic field strength around a magnet at different distances. The readings are: 0.2 Tesla at 2 cm, 0.1 Tesla at 4 cm, and 0.05 Tesla at 8 cm from the magnet. Analyze the data and explain the relationship between magnetic field strength and distance.

Answer: The magnetic field strength decreases as the distance from the magnet increases, approximately following an inverse square law or similar decay pattern.

Question 1: Explain how magnetic fields are utilized in electric motors. Include the role of magnetic forces and the concept of electromagnetic induction.

Answer: Electric motors convert electrical energy into mechanical energy using magnetic fields. Current-carrying conductors experience a force in a magnetic field (Lorentz force), causing rotation. Electromagnetic induction is used in generators and motors to produce current and motion, respectively, utilizing changing magnetic flux to induce voltage.

Question 2: Multiple Choice: Which of the following materials is most suitable for making a magnetic core in transformers?

Answer: Soft iron