If the percentage error in measurement of radius of a sphere is 2%, the percentage error in volume is MCQ with Answer and Explanation

Explanation:
The area under velocity-time graph gives displacement when direction is considered (signed area), and distance travelled when absolute values are taken (unsigned area). For unidirectional motion, both are equal. Velocity is rate of change of displacement, so integrating velocity over time yields displacement. This graphical interpretation is fundamental in kinematics. Memory tip: Slope of v-t graph = acceleration; area under v-t graph = displacement. Competitive exams often combine graph analysis with conceptual understanding to test depth of knowledge in motion topics.

Explanation:
Transformer, induction cooker, generator use induction. Heater and bulb use heating effect of current. Fuse melts by heat. Induction: changing magnetic field induces current.

Explanation:
A transformer core is subject to alternating magnetic fields, tracing out a hysteresis loop repeatedly. To minimize energy loss (hysteresis loss), the area of this loop must be small, requiring low coercivity (easily demagnetized). It also requires low retentivity so it loses magnetism rapidly when current stops. Steel, conversely, has high retentivity and coercivity, used for permanent magnets.