Question 1: Define an electromagnet and describe how it differs from a permanent magnet.

Answer: An electromagnet is a type of magnet in which the magnetic field is produced by an electric current flowing through a coil of wire. Unlike a permanent magnet, its magnetic field can be turned on or off and varies in strength depending on the current.

Question 2: Explain the role of the iron core in an electromagnet.

Answer: The iron core concentrates and amplifies the magnetic field produced by the coil, making the electromagnet stronger and more efficient.

Question 1: The magnetic field strength (B) of an electromagnet is 0.5 Tesla when a current of 3 Amperes flows through a coil with 200 turns and a core length of 0.5 meters. Calculate the magnetic field strength if the current is increased to 6 Amperes, assuming all other factors remain constant. (Use B ∝ I).

Answer: 1.0 Tesla

Question 1: Describe a simple experiment to demonstrate how increasing the number of turns in the coil affects the magnetic field strength of an electromagnet. Include variables to be controlled and safety precautions.

Answer: Students can wind more turns of wire around an iron core and measure the magnetic field strength using a compass or gauss meter. Variables to control include the current supplied to the coil and the core material. Safety precautions include ensuring the current does not overheat the wire and handling the coil carefully to avoid electric shock.

Question 1: A series of electromagnets with identical coils are tested with varying currents: 1A, 2A, 3A, 4A, and 5A. The measured magnetic field strengths are 0.2 T, 0.4 T, 0.6 T, 0.8 T, and 1.0 T respectively. Analyse the data to determine the relationship between current and magnetic field strength.

Answer: The data shows a direct proportional relationship between current and magnetic field strength, indicating B ∝ I.

Question 1: Explain how increasing the number of turns in an electromagnet's coil affects its magnetic field strength. Include any limitations or practical considerations.

Answer: Increasing the number of turns increases the magnetic field strength because the magnetic field is proportional to the number of turns times the current (B ∝ nI). However, adding more turns increases resistance, which may reduce current if voltage remains constant, potentially limiting the increase in magnetic field strength. Practical considerations include coil size, wire thickness, and heat dissipation.

Question 2: A student designs an electromagnet with 300 turns of wire powered by a 12V power supply. The wire has a resistance of 10 ohms. Calculate the current flowing through the coil and assess whether the electromagnet will function effectively.

Answer: Using Ohm's law: I = V / R = 12V / 10Ω = 1.2A. With this current, the electromagnet should generate a magnetic field proportional to the current and number of turns, making it effective for typical applications.

Question 1: Identify two industries or everyday devices that rely on electromagnets. Explain the role they play in these applications.

Answer: Electromagnets are used in scrap yards to lift heavy metal debris by attracting ferrous materials. They are also used in electric relays and motors to control electrical circuits and convert electrical energy into mechanical movement.