The resistance of an ideal voltmeter is MCQ with Answer and Explanation

Explanation:
This is based on the conservation of angular momentum (L = Iω), where 'I' is the moment of inertia and 'ω' is angular velocity. When the boy extends his arms, mass moves further from the axis of rotation, increasing his moment of inertia (I). Since 'L' is conserved, an increase in 'I' must result in a decrease in angular velocity (ω).

Explanation:
Hydraulic brakes operate on Pascal's Law. It states that an external pressure applied to an enclosed, incompressible fluid is transmitted undiminished equally in all directions throughout the fluid volume. When force is applied to the small brake pedal cylinder, it exerts a large pressure that is transmitted to the larger wheel cylinders, amplifying the force.

Explanation:
Dispersion: separation due to different refractive indices for different colours. Refraction is bending. Scattering (Tyndall effect) makes sky blue. Total internal reflection in optical fibers.