Engineering

Question 1

1An energy audit identifies

Easy

A. the cost of food B. where energy is wasted and how to save it C. the number of staff D. tax owed

Question 2

2A solar water heater costs GH¢3,000 and saves GH¢500 a year in electricity. What is the payback period?

Easy

A. 15 years B. 5 years C. 6 years D. 2 years

Question 3

3U-value in building insulation measures

Hard

A. the rate of heat transfer through a material B. its weight C. its colour D. its cost

Question 4

4Insulating a building reduces

Easy

A. water supply B. heat transfer and energy use for cooling C. light D. air quality

Question 5

5LED bulbs are more energy-efficient than incandescent bulbs because they

Easy

A. use gas B. convert more electricity into light and less into heat C. are bigger D. are brighter always

Question 6

6Replacing ten 60 W bulbs with 9 W LEDs used 5 hours a day saves how much energy per day?

Hard

A. 0.51 kWh B. 3 kWh C. 2.55 kWh D. 0.45 kWh

Question 7

7Efficiency of a motor that converts 800 J of 1,000 J input into useful work is

Easy

A. 125% B. 80% C. 20% D. 8%

Question 8

8Replacing filament bulbs with LED bulbs saves energy because LEDs

Easy

A. need no electricity B. convert more of the electricity into light and less into heat C. use higher voltage D. are brighter at all times

Question 9

9Switching off appliances at the socket saves

Easy

A. gas B. nothing C. water D. standby power

Question 10

10An energy-efficient refrigerator has

Easy

A. more noise B. a lower rating C. a higher energy rating label D. no label