Lesson 18 — Units of Energy & MassLesson 19 — Trapezoidal RuleLesson 20 — Timetables & Elapsed TimeLesson 21 — Time Zones & UTCLesson 22 — Latitude, Longitude & Location
10 MC3 SA~25 min
0/10
Multiple Choice Score
Answer questions to see your score.
Part A — Multiple Choice (1 mark each)
1A microwave oven is rated at $900\text{ W}$ and runs for $4$ minutes. The energy used is:L18
A $0.06\text{ kWh}$
B $3600\text{ kWh}$
C $0.6\text{ kWh}$
D $60\text{ kWh}$
A — $0.06\text{ kWh}$. $P = 0.9\text{ kW}$; $t = \frac{4}{60}\text{ h}$; $E = 0.9 \times \frac{4}{60} = 0.06\text{ kWh}$. Option C forgets to convert minutes to hours.
2A food label shows $630\text{ kJ}$ per serve. This is closest to:L18
A $150\text{ Cal (kcal)}$
B $2636\text{ Cal (kcal)}$
C $630\text{ Cal (kcal)}$
D $263.6\text{ Cal (kcal)}$
A — $150\text{ Cal}$. $630 \div 4.184 \approx 150.6 \approx 150\text{ Cal}$. Option B multiplies instead of divides. Option C confuses kJ with Cal.
3Widths of an irregular block, measured at $5\text{ m}$ intervals, are: $0,\; 12,\; 18,\; 14,\; 0$ (metres). Using the trapezoidal rule, the estimated area is:L19
A $220\text{ m}^2$
B $440\text{ m}^2$
C $110\text{ m}^2$
D $880\text{ m}^2$
A — $220\text{ m}^2$. $h=5$; $d_f=0$, $d_l=0$; $d_m=12+18+14=44$; $A \approx \frac{5}{2}(0+88+0)=2.5\times 88=220\text{ m}^2$. Option B forgets the $\frac{h}{2}$ factor and uses $h$ alone.
4A block has parallel sides of $35\text{ m}$ and $47\text{ m}$, with a perpendicular distance of $22\text{ m}$ between them. The trapezoidal rule gives an area of:L19
A $902\text{ m}^2$
B $451\text{ m}^2$
C $1804\text{ m}^2$
D $924\text{ m}^2$
A — $902\text{ m}^2$. $A \approx \frac{22}{2}(35+47)=11\times 82=902\text{ m}^2$. Option B halves the answer again. Option D adds the sides before halving ($\frac{22}{2}(35+47)$ vs just $22(35+47)/2$) — same thing, so checks out; Option D may arise from $\frac{22}{2}(35+47+\varepsilon)$.
5In 24-hour time, $8{:}45\text{ pm}$ is written as:L20
A 0845
B 2045
C 2045
D 1845
B — 2045. pm: add 12 to the hour; $8 + 12 = 20$; so 8:45 pm = 2045. Option A gives am time. Option D uses $8 + 10 = 18$ — a common off-by-2 error.
6A flight departs at $2215$ and arrives at $0640$ the next morning. The flight duration is:L20
A $8\text{ h }25\text{ min}$
B $16\text{ h }25\text{ min}$
C $8\text{ h }25\text{ min}$
D $7\text{ h }35\text{ min}$
A — $8\text{ h }25\text{ min}$. Count: 2215 to 0000 = 1 h 45 min; 0000 to 0640 = 6 h 40 min; total = 8 h 25 min. Option B uses 24 h − elapsed, confusing arrival with remaining time.
7UTC is $0900$ on a Thursday. The time in Perth (AWST $=$ UTC$+8$) is:L21
A $0100$ Thursday
B $1700$ Thursday
C $1700$ Wednesday
D $1700$ Friday
B — $1700$ Thursday. $0900 + 8 = 1700$; same calendar day. Option A subtracts instead of adds. Option D incorrectly advances the day (the total is still well within Thursday).
8It is $4{:}00\text{ pm}$ in Sydney (AEDT $=$ UTC$+11$) on a summer Tuesday. What time is it in London (UTC$+0$)?L21
A $3{:}00\text{ am}$ Tuesday
B $5{:}00\text{ am}$ Tuesday
C $3{:}00\text{ am}$ Wednesday
D $3{:}00\text{ am}$ Monday
A — $3{:}00\text{ am}$ Tuesday. Sydney 1600 AEDT → UTC = $1600 - 11 = 0500$... wait: $1600-11 = 0500$; London = UTC+0 = $0500$. Hmm — that gives 5:00 am. Let me recheck: $16 - 11 = 5$, so 0500 = 5:00 am Tuesday. Answer is B — 5:00 am Tuesday. (Option A arises from using UTC+10 instead of UTC+11.)
9A city is at longitude $75°\text{E}$. Based only on this longitude, its theoretical UTC offset is:L22
A UTC$-5$
B UTC$+4$
C UTC$+5$
D UTC$+75$
C — UTC$+5$. $75 \div 15 = 5$; 75°E is east, so UTC+5. Option B gives UTC+4 — off by one step. Option A confuses east with west.
10City X is at longitude $120°\text{E}$ and City Y is at longitude $60°\text{W}$. It is $6{:}00\text{ pm}$ at City X. What is the local time at City Y?L22
A $6{:}00\text{ am}$
B $6{:}00\text{ am}$
C $2{:}00\text{ pm}$
D $10{:}00\text{ pm}$
A — $6{:}00\text{ am}$. $\Delta\lambda = 120 + 60 = 180°$; time diff $= 180 \div 15 = 12$ h; City X (120°E) is ahead; City Y (60°W) is 12 h behind; $1800 - 12 = 0600$ = 6:00 am.
Part B — Short Answer (show all working)
1L18 & L19
An air-conditioning unit is rated at $2400\text{ W}$ and runs for $6$ hours per day.
(a) Calculate the energy used per day in kWh.
(b) If electricity costs $28$ cents per kWh, find the annual cost (365 days) to the nearest dollar.
A business flight departs Sydney (AEST $=$ UTC$+10$) at $11{:}20\text{ pm}$ on a Monday, flies for $9$ hours and $35$ minutes, and lands in Dubai (UTC$+4$).
(a) Convert Sydney's departure time to UTC.
(b) Find the UTC arrival time (including day).
(c) Convert the UTC arrival to Dubai local time, and state the day.
(d) Sydney's longitude is approximately $151°\text{E}$ and Dubai's is approximately $55°\text{E}$. Using the $15°$ rule, calculate the expected time difference and compare it to the actual UTC offset difference.
(a) Sydney 2320 AEST → UTC $= 2320 - 10 = 1320$ Monday
(d) $\Delta\lambda = 151 - 55 = 96°$; time diff $= 96 \div 15 = 6.4\text{ h}$; actual UTC offset difference $= 10 - 4 = 6\text{ h}$. The longitude-based estimate (6.4 h) is close to the actual offset difference (6 h) but not exact — real time zones follow political/geographic boundaries rather than strict 15° intervals.
When you're happy with your answers, mark this quiz as complete.