Two machines complete the same amount of work, but Machine A does it in half the time compared to Machine B. Which machine has a greater power output?

Appeared in: RRB Nsg. Superintendent-2026 (Shift -2nd)

Explanation

Power is the rate at which work is done, defined by the formula: Power = Work / Time.
The question states that both machines perform the same amount of work, making 'Work' a constant value in this comparison.
When work is constant, power is inversely proportional to the time taken. A shorter time results in a higher power output.
Since Machine A completes the work in half the time of Machine B, it operates at a higher power level.

Option A: This is incorrect. Equal power output would require both machines to take the same amount of time to perform the same amount of work.
Option B: This is incorrect. The relationship between power, work, and time is explicitly defined by the physics formula P = W/t, which allows for a definitive conclusion.
Option D: This is incorrect. Machine B takes a longer time to perform the same amount of work, which, according to the formula P = W/t, results in a lower power output.

Visual 1: Formula Diagram - A simple visual showing the formula Power = Work / Time, highlighting that if 'Work' is constant, 'Power' and 'Time' are inversely proportional.
Visual 2: Bar Chart - A chart comparing the power output of Machine A and Machine B, with Machine A's bar being twice as high as Machine B's bar, illustrating it has double the power.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Relationship between Power, Work, and Time as background academic context rather than a clinical decision trigger.
While this is a physics concept, understanding power is relevant in medicine. For example, a defibrillator delivers a high amount of electrical energy (work) in a very short time, resulting in a very high power output to restart the heart.
The power of human muscles, defined as the work they perform per unit of time, is a key factor in physical performance, rehabilitation assessments, and understanding the energy expenditure during different activities.
What if? If Machine A did the same work but took twice the time of Machine B, then Machine B would have the greater power output, as it would be working at a faster rate.

How to Approach the Question

Identify the physical quantities mentioned in the question: work, time, and power.
Recall the fundamental relationship that connects them: Power is defined as Work divided by Time (P = W/t).
Analyze the conditions given: The work done (W) is the same for both machines. The time for Machine A (t_A) is half the time for Machine B (t_B).
Apply the inverse relationship: Since work is constant, the machine that takes less time must have a higher power output.
Conclude that Machine A, which works faster (less time), has the greater power output.

Concept Tested & Keywords

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Practise the full RRB Nsg. Superintendent-2026 (Shift -2nd)

Attempt every question from this paper in a timed mock, then review the full solution for each one.