A body is lifted vertically through a height h. The work done against gravity is stored as:
A. Thermal energy
B. Kinetic energy
C. Gravitational potential energy
D. Elastic potential 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:
Surface tension is defined as Force per unit length (F/L). Dimensional formula: [MLT⁻²] / [L] = [MT⁻²]. A spring constant (k) is defined by Hooke's Law as Force per unit extension (F/x), which also has dimensions [MLT⁻²] / [L] = [MT⁻²]. Thus, both share the same dimensional formula.
Explanation:
Electrical resistance (R) is Voltage/Current. Voltage (V) is Work/Charge. Work is [ML^2T^-2] and Charge is [AT]. So, V = [ML^2T^-3A^-1]. Therefore, R = V/A = [ML^2T^-3A^-2]. Memorizing the dimensional formula for resistance is highly recommended for competitive exams.
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