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Question

If a young son works quickly for 2 hours and prepares 16 items in a day, and his old father works slowly for 8 hours and prepares 24 items a day, which of the following is true.

This question was previously asked in
RRB ALP/Technician 2018 CBT 2 Electronics Mechanic Question Paper (23-Jan-2019) (Shift 1)
The correct answer is

The son has more power

This question asks us to compare the productivity or rate of work between a son and his father. In physics, the rate at which work is done is defined as power. Although the question uses terms like "quickly" and "slowly," we can quantify their work rates based on the number of items prepared and the time taken.

Understanding Power in Work Rate Problems

In the context of work rate, power can be thought of as the amount of 'work' (in this case, items prepared) done per unit of 'time'. The formula for power is generally:

\[ \text{Power} = \frac{\text{Work Done}}{\text{Time Taken}} \]

Here, 'Work Done' is represented by the number of items prepared.

Calculating the Son's Power

Let's calculate the rate at which the son prepares items. We are given:

  • Son's items prepared = 16 items
  • Son's time worked = 2 hours

Using the power formula:

\[ \text{Son's Power} = \frac{\text{Son's items prepared}}{\text{Son's time worked}} \]

\[ \text{Son's Power} = \frac{16 \text{ items}}{2 \text{ hours}} = 8 \text{ items/hour} \]

So, the son works at a rate of 8 items per hour.

Calculating the Father's Power

Next, let's calculate the rate at which the father prepares items. We are given:

  • Father's items prepared = 24 items
  • Father's time worked = 8 hours

Using the power formula:

\[ \text{Father's Power} = \frac{\text{Father's items prepared}}{\text{Father's time worked}} \]

\[ \text{Father's Power} = \frac{24 \text{ items}}{8 \text{ hours}} = 3 \text{ items/hour} \]

So, the father works at a rate of 3 items per hour.

Comparing Power Levels: Son vs. Father

Now we compare the calculated power levels (work rates) for the son and the father:

  • Son's Power = 8 items/hour
  • Father's Power = 3 items/hour

Comparing these two values: \(8 \text{ items/hour} > 3 \text{ items/hour}\). This shows that the son prepares items at a faster rate than his father.

Therefore, based on the definition of power as the rate of doing work, the son has more power in preparing these items.

Analysis of Options

Let's examine the given options based on our calculations:

  1. The son has more energy
  2. The son has more power
  3. Both have equal energy
  4. Both have same power
  • Option 1: "The son has more energy". Energy is the capacity to do work. While the son is more powerful (works faster), we don't have enough information to compare their total energy output or capacity over different periods or under different conditions. This option is not directly supported by the given data, which focuses on rates.
  • Option 2: "The son has more power". Our calculation shows the son's work rate (8 items/hour) is higher than the father's (3 items/hour). This aligns with the definition of power in this context.
  • Option 3: "Both have equal energy". As discussed for Option 1, we cannot conclude this from the given data. Their rates of energy expenditure might differ significantly.
  • Option 4: "Both have same power". Our calculations (8 items/hour for the son and 3 items/hour for the father) clearly show that their power levels are different.

Based on the comparison of their work rates, the statement that the son has more power is true.

Revision Table: Key Concepts

Concept Definition in this context Calculation
Work Done Number of items prepared Given in the problem
Time Taken Hours spent working Given in the problem
Power (Work Rate) Items prepared per hour \( \frac{\text{Items}}{\text{Hours}} \)

Additional Information: Energy vs. Power

It's important to understand the difference between energy and power. Energy is the total amount of work that can be done or the capacity to do work. Power is the rate at which that work is done. Think of it like speed and distance:

  • Distance is like Energy (total work done).
  • Speed is like Power (rate of covering distance).

Someone who is more powerful can do the same amount of work in less time compared to someone less powerful. In this problem, the son is more powerful because he prepares items at a faster rate (more items per hour), even though the father prepares more items in total over a longer period (24 items vs 16 items).

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Similar Questions

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  7. The capacity to do work is called:

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Important Questions from Work Power Energy

  1. Which of the following is a clear example of potential energy?
  2. An object having the capability to do work is said to possess____________.

  3. One erg is equal to ________ Joule.

  4. An electric lamp of 100 W is used for 5 hours per day. How much energy will be consumed by the lamp for 3 days?

  5. When you compress a spring you do work on it. The elastic potential energy of the spring:

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