Physics

Power, Energy, and Efficiency

443 Questions

Power, energy, and efficiency are fundamental physics concepts that quantify work and the rate of doing work. Questions cover electrical energy consumption in kilowatt hours, the efficiency of thermodynamic cycles like the Brayton cycle, and mechanical power lifting loads. This topic is essential for general science and engineering exam preparation.

Electrical energy consumptionBrayton cycle efficiencyPower calculation formulasCommercial electricity unitsHydraulic lift mechanics

Power, Energy, and Efficiency Questions

Multiple choice maths ways to multiply and divide mental multiplication multiplication methods multiplication of numbers

A generator consumes 2.875 litres of diesel per hour.The quantity of diesel required to run the generator for 24 hours is ______ .

  1. $45$ litres
  2. $55$ litres
  3. $72$ litres
  4. $69$ litres
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\Rightarrow$  Diesel consumes by generator in $1\,hour$ = $2.875\,liters.$

$\Rightarrow$  Diesel consumes by generator in $24\,hours=24\times 2.875\,liters$
$\therefore$  Diesel consumes by generator in $24\,hours=69\,liters$.

Multiple choice maths ways to multiply and divide mental multiplication multiplication methods multiplication of numbers

A machine produces $2800$ screws in a day. Which of the following is the best estimate of the number of screws produced in 2 days?

  1. $3500$
  2. $5000$
  3. $3000$
  4. $2900$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A machine produces $2800$ screws in a day.

Hence it will produce $2800\times2$ screws in $2$ days
$=5600$ screws in $2$ days
The best estimate of the number of screws produced in $2$ days is $5000$
Hence Option B

Multiple choice
  1. power = energy ÷ time

  2. energy = power ÷ time

  3. power = time ÷ energy

  4. power = energy x time

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Power is defined as the rate at which energy is transferred or work is done, expressed as P = E/t.

Multiple choice infrastructure in india infrastructure tertiary sector economics

______ of the total installed capacity power is in private sector.

  1. 15%

  2. 29%

  3. 33%

  4. 45%

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Based on historical data for the Indian power sector, the private sector's share of installed capacity has grown significantly, with 29% being a commonly cited figure in textbooks for this period.

Multiple choice
  1. 10

  2. 100

  3. 1,000

  4. 10,000

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The prefix kilo- denotes a factor of 1,000. Therefore, one kilowatt is equal to 1,000 watts.