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Induction in a Moving Coil?
A coil is placed in a magnetic field and attached to a rotating disc that can move at varying speeds. If the rotation speed of the disc is doubled, will the induced emf in the coil also double? Explain your reasoning, considering the factors that influence the induced emf.
Lenz's Law in Practice?
A coil is placed near a bar magnet. When the bar magnet is slowly moved towards the coil, a current is induced in the coil. However, if the bar magnet is moved rapidly towards the coil, the direction of induced current is reversed. Explain the difference in induced current in both scenarios.
Magnetic Domain Walls: A Quantum Conundrum?
Consider a ferromagnetic material exhibiting spontaneous magnetization. Explain how the formation of magnetic domain walls affects the material's overall magnetic moment, and discuss the implications of quantization of magnetic flux on domain wall stability.
Electric Shielding Effect?
A cylindrical shell of radius R has a charge +Q uniformly distributed on its curved surface. What is the electric field at a distance r < R from the center of the shell? Explain your reasoning with suitable diagrams and equations.
Electric Field Due to Multiple Charges?
A thin rod of length 1m is bent into a semicircle and placed on a table with its diameter along the x-axis. A point charge of +4μC is placed at the center of the semicircle and another point charge of -2μC is placed at a distance of 20cm from the center along the y-axis. Calculate the electric field at a point P, which is 30cm away from the center along the x-axis.
Magnetic Field Lines in Coils?
In an electromagnetic coil, a long solenoid is wound with 100 turns of copper wire for every 5 cm length. What effect, if any, will occur if the number of turns is doubled, and what can be inferred about the magnetic field strength inside the coil?
Parallel Plate Capacitor Dilemma
A 2 μF parallel plate capacitor is charged to a potential difference of 300 V. If the distance between the plates is suddenly doubled, how does the electrostatic potential energy stored in the capacitor change, and why?
Charging Porcelain Insulators?
You have a set of identical porcelain insulators. Explain the outcome when you rub a glass rod against one insulator and then bring it close to the remaining insulators without touching them. Assume that the glass rod is rubbed with silk cloth and becomes positively charged.
Magnetic Field Around a Coil?
A coil of insulated copper wire carrying a current of 5 A is placed near a compass needle. What would be the direction of the magnetic field lines around the coil, and how would it affect the compass needle's orientation?
Capacitor in a Non-Uniform Field?
A parallel plate capacitor is placed in a non-uniform electric field. If one plate is taken out of the field, how will the value of capacitance change, and what effect will it have on the stored charge?
Resistance in a Parallel Circuit?
In a parallel configuration of two resistors, one with a resistance of 10 Ω and the other with a resistance of 20 Ω, a voltage of 20 V is applied across each. How do the equivalent resistance and current through each resistor compare to their individual values?
Magnetic Field and Torque?
A bar magnet of length 10 cm is placed inside a solenoid of 100 turns per meter. If the solenoid carries a current of 2 A, what is the magnitude of the torque experienced by the bar magnet? Assume the magnetic moment of the bar magnet is 0.5 A·m².
Resistors in Parallel: A Conundrum
Three identical light bulbs, each with a resistance of 10 ohms, are connected in parallel across a 100-volt power source. If two of the bulbs are removed, how will the equivalent resistance of the remaining configuration change, and what will be the new current through the circuit?
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