Q. A solenoid produces a uniform magnetic field inside it. What factors affect the strength of this magnetic field?
A.Length of the solenoid
B.Number of turns per unit length
C.Current through the solenoid
D.All of the above
Solution
The strength of the magnetic field inside a solenoid is affected by the number of turns per unit length and the current flowing through it, as well as the length of the solenoid.
Q. A solenoid with a length of 1 m and a cross-sectional area of 0.01 m² carries a current of 5 A. If the magnetic field inside the solenoid is uniform, what is the magnetic field strength?
A.0.1 T
B.0.2 T
C.0.5 T
D.1 T
Solution
The magnetic field inside a solenoid is given by B = μ₀ * (N/L) * I. Assuming N/L = 1 for simplicity, B = μ₀ * I = 4π × 10^-7 T*m/A * 5 A = 0.5 T.
Q. A solid cone rolls down an incline. If its height is h, what is the relationship between its potential energy and kinetic energy at the bottom?
A.PE = KE
B.PE = 2KE
C.PE = 3KE
D.PE = 4KE
Solution
For a solid cone rolling down an incline, the potential energy at height h is converted into translational and rotational kinetic energy, leading to PE = 2KE.
Q. A solid cylinder and a hollow cylinder of the same mass and radius are released from rest at the same height. Which one will have a greater speed at the bottom?
A.Solid cylinder
B.Hollow cylinder
C.Both have the same speed
D.Depends on the mass
Solution
The solid cylinder has a smaller moment of inertia compared to the hollow cylinder, thus it will have a greater speed at the bottom.
Q. A solid cylinder of radius R rolls down a frictionless incline. What is the ratio of its translational kinetic energy to its total kinetic energy at the bottom?
A.1:1
B.2:1
C.1:2
D.3:1
Solution
At the bottom, total kinetic energy = translational + rotational. For a solid cylinder, the ratio of translational to total kinetic energy is 2:1.
Q. A solid cylinder rolls down an incline of height h. What fraction of its total mechanical energy is kinetic energy at the bottom?
A.1/3
B.1/2
C.2/3
D.1
Solution
At the bottom, total mechanical energy is converted into kinetic energy, which is the sum of translational and rotational kinetic energy. For a solid cylinder, 2/3 of the energy is kinetic.
Q. A solid sphere and a hollow sphere of the same mass and radius are released from rest at the same height. Which one will have a greater linear speed when they reach the ground?
A.Solid sphere
B.Hollow sphere
C.Both have the same speed
D.Depends on the mass
Solution
The solid sphere will have a greater linear speed because it has a smaller moment of inertia, allowing it to convert more potential energy into translational kinetic energy.
Q. A solid sphere and a hollow sphere of the same mass and radius are released from rest at the same height. Which one reaches the bottom first?
A.Solid sphere
B.Hollow sphere
C.Both reach at the same time
D.Depends on the surface
Solution
The solid sphere reaches the bottom first because it has a lower moment of inertia, allowing it to convert more potential energy into translational kinetic energy.