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Induction on a Rotating Disk?
A copper disk of radius 20 cm is rotating about its central axis at an angular speed of 20 rad/s. Describe the direction of the induced current in the disk when the rotation is reversed.
Magnetic Field Around a Current-Carrying Wire?
A 2 A current is carried through a wire of radius 1 cm. A second wire, also carrying 2 A, is placed parallel to the first wire at a distance of 5 cm. What will be the nature of the magnetic field lines around the second wire?
A Bungee Jumper's Surprise
Rahul, a bungee jumper, jumps from a 200 m high bridge. His bungee cord is designed to stretch by 50 m before releasing the stored elastic potential energy. Calculate the speed with which Rahul hits the water on the ground, given that the centre of mass of his body comes to rest momentarily at 20 m above the ground.
Mass and Gravitational Force?
Suppose a planet with a mass twice that of the Earth is discovered. If a body of mass 100 kg is placed on its surface, how will the gravitational force acting on it compare to the force acting on the same body on the Earth's surface?
Magnetic Domains: A Microscopic Perspective?
Consider a ferromagnetic material with a non-uniform magnetic domain structure. Describe how the arrangement of magnetic domains within the material influences its macroscopic magnetic properties, such as magnetization and coercivity. What implications does this have for the material's use in magnetic storage devices?
Can a Moving Charge Create a Magnetic Field?
A hypothetical charged particle is accelerated from rest to a high velocity in a time interval of 10^-6 seconds. Is it possible for this moving charge to create a magnetic field in the vicinity of the path it is moving in, even if the acceleration is very gradual and takes place over a long distance? Assume the charged particle is a proton.
Magnetic Field and Induction?
A circular loop of wire is placed in a varying magnetic field generated by an AC generator. Explain how the direction of the induced current in the loop changes as the south pole of the magnet approaches the loop and then recedes.
Tipping Point of Gyroscope?
A gyroscope is mounted on a frictionless rotating turntable. If the gyroscope's angular velocity is 2 rad/s about its axis of symmetry, and it experiences a torque of 0.5 Nm perpendicular to its axis, determine the minimum angular velocity the turntable must have to prevent the gyroscope from tipping.
Magnetic Field around a Current Loop?
A circular coil of wire of 50 turns and a radius of 20 cm carries a current of 2 A. Calculate and describe the direction and magnitude of the magnetic field at the center of the coil. Consider the effect of doubling the current and halving the number of turns on the magnetic field strength.
A Car's Braking System - Efficiency and Safety?
A car is moving at a speed of 50 m/s when the driver suddenly applies the brakes. The car's mass is 1500 kg. If the brakes are applied uniformly over a distance of 20 m, will the car come to a complete stop? If not, what would be the remaining speed of the car and how does it relate to the coefficient of kinetic friction between the car's tires and the road?
Capacitance of a Spherical Shell?
A spherical shell of radius 10 cm has a charge of 1 μC distributed uniformly over its surface. If the shell is placed near a small charged particle of mass 4 × 10^(-7) kg and charge 2 × 10^(-8) C, will it be repelled or attracted, and what will be the magnitude of the electrostatic force on the particle? Explain your reasoning.
Parallel Plate Capacitor in Space?
Two parallel plate capacitors of capacitance 100 μF each are connected in series. If one capacitor is placed on the surface of the Earth and the other is taken to a height of 2 R (where R is the radius of the Earth), how will the equivalent capacitance of the circuit change, and why?
Angular Momentum Conservation in Rotational Motion?
In a laboratory experiment, a top spinning on a string is released from rest when the string's length is halved. Analyze how the angular momentum of the top changes and relate it to the conservation of angular momentum principle.
A Spherical Capacitor Conundrum?
Two concentric spherical shells of radii 10 cm and 20 cm have the same charge of 6 μC. What potential difference would be measured across the 10-15 cm region, where the inner shell has been removed?
What's the Effect of Resistance on the Efficiency of a Lamp?
A 100 W light bulb has a resistance of 10 Ω. If the power consumed by the bulb increases to 110 W, how will the increase in power affect the efficiency of the bulb, assuming the supply voltage remains the same? Assume the efficiency of the bulb is directly proportional to its resistance.
Induction in Rotating Coils ?
A coil of wire is placed in a magnetic field and rotated at a constant angular speed. Explain how the induced emf in the coil changes as the rotation speed increases, assuming the magnetic flux remains constant.
Relative Velocity Puzzle?
A car A is moving with a uniform velocity of 20 m/s due east. A car B is moving with a uniform velocity of 15 m/s due north. If a bird flying at a velocity of 30 m/s in a direction making an angle of 60° with the horizontal meets car A, explain the relative velocity of the bird with respect to car B.
A Rotating Wheel's Inertia?
A bicycle wheel has a mass of 8 kg and a radius of 0.5 m. It is initially at rest. If a wheel has 50% of its kinetic energy at rotation, calculate the linear velocity of the bicycle's center of mass when the wheel is rotating with an angular velocity of 10 rad/s.
Magnetic Field Around a Current-Carrying Wire?
Consider a long straight copper wire carrying a current of 2 A from east to west, placed inside a copper ring. If the ring is connected to a battery and the current through the ring increases by 4 A, how will the magnetic field around the wire change?
Limiting the Current?
A fuse wire of resistance 2 ohms and a melting point of 80°C is used to limit the current in a circuit. If the circuit draws a current of 2A and the voltage across the fuse is 12V, how can the melting point be further reduced without changing the fuse wire's resistance? Explain your reasoning.
Inclined Plane and Friction?
A block of wood of mass 5 kg is placed on an inclined plane of angle 30°, where the coefficient of kinetic friction is 0.2. If a force of 25 N is applied parallel to the plane, explain the situation with a neat diagram and describe the net force acting on the block in terms of its components.
Electric Field in a Conductor
A spherical conductor of radius R has a point charge q placed at its center. If a second point charge -2q is brought near the conductor, what will happen to the electric field inside the conductor?
How does a capacitor behave when connected to a DC power source and an AC power source?
A parallel plate capacitor with a dielectric constant of 3 and a capacitance of 10 μF is connected to a DC power source and an AC power source. What differences, if any, do you observe in the capacitor's behavior and how do you explain them in terms of electrostatic potential and capacitance?
Ferric Metals in Induction
The magnetic field of a coil with ferric metal core is found to be stronger than one with an air core. Would this be true if the coil is stationary, and the strength of the magnetic field is measured when an alternating current is passed through it?
Lenz's Law Insight?
A coil of 100 turns is placed in a magnetic field that is decreasing at a rate of 0.1 T/s. If the coil's resistance is 5 Ω and it is connected to a 0.1 H inductor, will a current flow in the coil? What would be the direction of the induced current?
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