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Leaving Cert Technology: Work, power & energy cost

How often Work, power & energy cost comes up on the Technology papers, every year it was asked, and questions to try.

HL Asked on 7 of the last 9 Higher Level papers, most recently in 2025. most years

OL Asked on 5 of the last 9 Ordinary Level papers, most recently in 2024.

Work, power & energy cost, Higher Level(8 marks)

Quick ones on Work, power & energy cost.

(a)A 250 N force pushes a trolley 8 m. How much work is done?
  1. 31.25 J
  2. 2000 J
  3. 258 J
(b)How many joules are there in 1 kWh?
  1. 3600 J
  2. 1000 J
  3. 3 600 000 J
(c)A 20 kg box is lifted 3 m (g = 9.81 m/s²). What potential energy does it gain?
  1. 588.6 J
  2. 196.2 J
  3. 60 J
Show the answers

(a) 2000 J

(b) 3 600 000 J

(c) 588.6 J

Your turn: Higher Level questions on Work, power & energy cost.

Higher Level

Asked on 7 of the last 9 Higher Level papers, most recently in 2025. most years

Every paper, year by year

YearWhere it came up
2025A5
2024B2c, B3b
2023A3, A5
2022Not asked
2021Not asked
2019A11, B2a
2018A12
2017A4, A7
2016B3b

Links open the State Examinations Commission’s paper for that year.

More Work, power & energy cost questions

Work, power & energy cost, 3 marks

A meter reading rises from 45 210 to 45 530 units. At 25c per unit in this example, what is the cost?

  1. €8.00
  2. €800.00
  3. €80.00
Show the answer

€80.00

Units used = 45 530 − 45 210 = 320 kWh. Cost = 320 x €0.25 = €80.00. One unit on an electricity meter is one kilowatt-hour.

Work, power & energy cost, 3 marks

A 1.5 kW motor does 90 000 J of work. How long does it take?

  1. 0.017 s
  2. 60 s
  3. 135 000 s
Show the answer

60 s

t = W / P = 90 000 J / 1500 W = 60 s. Change kW to W first so that the units match.

Work, power & energy cost, 2 marks

One watt is equal to:

  1. One joule per second
  2. One newton per metre
  3. One joule per hour
Show the answer

One joule per second

Power is the rate of doing work or converting energy. 1 W = 1 J/s, so a 60 W lamp converts 60 joules of electrical energy every second.

Ordinary Level

Asked on 5 of the last 9 Ordinary Level papers, most recently in 2024.

Every paper, year by year

YearWhere it came up
2025Not asked
2024A9
2023Not asked
2022Not asked
2021B3c
2019B3c
2018A8
2017A2
2016Not asked

Links open the State Examinations Commission’s paper for that year.

More Work, power & energy cost questions

Work, power & energy cost, 3 marks

A 2 kW heater runs for 3 hours. How much energy does it use?

  1. 1.5 kWh
  2. 5 kWh
  3. 6 kWh
Show the answer

6 kWh

Energy in kWh = power in kW × time in hours = 2 × 3 = 6 kWh. One kWh is one unit on an electricity bill.

Work, power & energy cost, 3 marks

A force of 200 N pushes a box 5 m. How much work is done?

  1. 205 J
  2. 1000 J
  3. 40 J
Show the answer

1000 J

Work = force × distance = 200 N × 5 m = 1000 J. One joule is the work done when a force of 1 N moves through 1 m.

Work, power & energy cost, 3 marks

Electricity costs 30c per kWh. What do 20 kWh cost?

  1. €6.00
  2. €0.60
  3. €60.00
Show the answer

€6.00

Cost = units × price per unit = 20 × €0.30 = €6.00. Watch the cents: 30c is €0.30, not €30.

Other Technology topics

All of Leaving Cert Technology