IBC Quiz #206
22/05/2026
REKHA CM
Class 8
GR International public school
Deepthi Priya R
Class 8
DDPS
Indu shree
Class 8
Sri Sharada English High school
Lokjeeth
Class 8
Vidya jyothi school
Nayana
Class 8
Sri sharada English high school
Pavan
Class 8
Sri Vasavi Vidya samsthe sira
Harsha M
Class 4
Thyagaraju central school
Abhishta Bhat
Class 8
KSVK International School
L Kushil Prasad
Class 4
St Michel's English School
Unnathi gowda k v
Class 8
Bhavishyath public school
Note: Quiz prizes will be awarded to ten randomly selected students who submit correct answers before the deadline. Winners will be declared on the website and the weekly newsletter.
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Previous Week Quizzes
IBC Quiz #206
May 22, 2026
At PurePath Design Lab, a student health-tech team is testing low-cost water filters for places where safe drinking water is difficult to access.
The dirty-water sample contains:
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Leaves and grit
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Muddy particles
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Fine suspended dirt
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Unpleasant smells
The lab does not want a filter that simply makes the water look clean.
It wants the prototype that is most likely to:
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Remove large and fine contamination in stages
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Reduce unpleasant smells
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Keep the water inside the filter long enough for proper cleaning
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Avoid weak designs in which water escapes full filtration
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Remain reliable when judged as a real product
The team has built four prototype filters.
At first glance, more than one may look convincing — but only one should be approved.
Before You Solve
Each layer has a specific job:
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Gravel = large-particle stage
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Coarse sand = medium-particle stage
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Fine sand = fine suspended dirt stage
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Activated charcoal = smell-reduction stage
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Cotton or filter cloth = final fine-cleaning stage
Important clue
A safe filter is not the one with the most layers. It is the one that makes water pass through the correct stages, in the correct order, for long enough, without bypassing any part of the filter.
Reference Clues
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The full filter body height is 10 units.
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Gravel must be at least 2 units deep.
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Coarse sand must be at least 2 units deep.
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Fine sand must be at least 2 units deep.
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Activated charcoal must be at least 2 units deep.
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Cotton must be at least 1 unit deep.
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A good prototype must have complete stages, sufficient layer depth, no bypass path and controlled flow.
Final Question
Which filter prototype would you approve for real use?
A team at ClearDrop Kids Lab is helping their school choose a water filter for a clean-water project.
The dirty water they need to clean contains:
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Leaves and grit
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Muddy water
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Tiny dirt particles
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Unpleasant smells
The team has built four filter designs.
The school wants the design that is most likely to:
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Stop the larger dirt particles first
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Clean smaller dirt particles later
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Reduce unpleasant smells
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Give the water enough time to pass through the filter
Only one design is the best choice.
Before You Solve
Different materials help in different ways:
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Gravel catches larger pieces of dirt first
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Coarse sand traps smaller dirt particles
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Charcoal helps reduce unpleasant smells
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Cotton or cloth catches the finest dirt near the end
Important clue
A good filter is not just about having the right materials. The order matters, the flow matters and the cleaning layers must be thick enough to do their job properly.
Reference Clues
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The full filter section is divided into four equal parts.
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A main cleaning layer should be at least one full part tall.
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If a cleaning layer is smaller than one full part, it may not clean effectively.
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Water should not pass through too quickly.
Final Question
Which filter design should the school choose?
IBC Quiz #205
May 15, 2026
Luca and Elena are taking part in a school physics competition. Their teacher, Dr Marcus Webb, sets up a simple light experiment in a dark classroom.
Four lamps are placed at different distances from four sensor panels.
Dr Webb explains:
“The brightness (intensity) received by each panel depends on the lamp power and the distance from the lamp.”
Formula:
I = (P / d²) × diffuser factor
Where:
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P = lamp power in watts
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d = distance in metres
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diffuser factor = 1 if there is no diffuser
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diffuser factor = 0.5 if a diffuser is used
Lamp Setup
Additional Condition:
Dr Webb says:
“For the sensor system to work properly, the ideal intensity is 5.”
Efficiency Score Formula:
Efficiency Score = | I − 5 |
A smaller efficiency score means the panel is closer to the ideal intensity.
QUESTION
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Arrange the panels from brightest to dimmest.
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Determine which panel has the best efficiency score (closest to intensity of 5).
Which option is correct?
Luca and Elena are taking part in a higher-level school physics competition. Their teacher, Dr Marcus Webb, sets up a light experiment in a dark classroom.
Four lamps are placed at different distances from four sensor panels. Some lamps also use diffuser screens that reduce the intensity of the light reaching the panels.
Dr Webb explains:
“The brightness (intensity) received by each panel depends on the lamp power, the distance from the lamp and whether a diffuser is used.”
Formula:
I = (P / d²) × diffuser factor
Where:
-
P = lamp power in watts
-
d = distance in metres
-
diffuser factor = 1 if there is no diffuser
-
diffuser factor = 0.5 if a diffuser is used
Optics Lab setup
Using Dr Webb's formula, calculate the light intensity (I) recorded at each panel.
Which set of values is correct, arranged from highest to lowest intensity (brightest to dimmest)?
