A body is lifted vertically through a height h. The work done against gravity is stored as:
A. Elastic potential energy
B. Kinetic energy
C. Gravitational potential energy
D. Thermal energy
Answer: Option C
Solution (By JKSSB Mock Tests)
When a body is lifted against gravity, work done (mgh) is stored as gravitational potential energy. This energy can be recovered when the body falls. Kinetic energy relates to motion, thermal to heat, elastic to deformed materials. The conservation of energy principle states that work done against conservative forces becomes potential energy. Formula: PE = mgh, where h is height above reference. Memory aid: 'Potential' means stored energy due to position. This conceptual question tests energy transformation understanding, frequently appearing in work-energy theorem applications in competitive exams.
Explanation:
Newton's second law: F = ma ⇒ a = F/m = 20 N / 5 kg = 4 m/s². Direct application of fundamental dynamics equation. Memory tip: Always convert to SI units first; here already in kg and N. Basic numerical testing F=ma application, commonly appearing in competitive exams to verify formula recall and unit handling.
Explanation:
A rectifier is an electrical device composed of one or more diodes that allows current to flow only in one direction. Its primary function is to convert Alternating Current (AC), which periodically reverses direction, into Direct Current (DC), which flows in only one direction. The reverse process (DC to AC) is done by an inverter.
Explanation:
Ohm's law applies to ohmic materials (metals) at constant temperature. Non-ohmic devices (diodes, filaments) have nonlinear V-I characteristics. Memory tip: 'Ohmic = linear V-I graph through origin; temperature must be constant'. Conceptual question testing Ohm's law limitations, frequently examined in competitive exams.
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