The relative permeability of a ferromagnetic material is MCQ with Answer and Explanation

Explanation:
The Doppler Effect is the apparent change in the frequency (and thus pitch) of a wave due to the relative motion between the source and the observer. As the ambulance approaches, sound waves get compressed, increasing the perceived frequency (higher pitch). As it moves away, waves stretch, lowering the frequency.

Explanation:
Coulomb (C).

Explanation:
Uniform acceleration means constant rate of change of velocity: a = dv/dt = constant. Thus v = u + at, a linear equation in t. Graph is straight line with slope = acceleration. Parallel to time axis (A) implies zero acceleration (constant velocity). Parabola (C) is for position-time under constant acceleration. Memory tip: 'v-t graph slope = acceleration; area = displacement'. This graph interpretation question tests kinematics fundamentals, frequently examined in competitive exams. Always link graph features to physical quantities: slope, area, intercepts have specific meanings in motion graphs.