Key relationship
q=fd/(d−f); only a real converging image can be collected on a screen.
Physics · Practical apparatus
Collect an image on a screen
Change object location and move the screen to the real image. Lens and mirror send the outgoing light to opposite bench sides, even though their positive-distance equations share the same form.
Open the interactive experiment →Collect an image on a screen
பொருள் இடத்தை மாற்றி திரையை உண்மை பிம்பத்தில் வைக்கவும். லென்சும் ஆடியும் வெவ்வேறு பக்கங்களில் ஒளியை அனுப்பும்.
Key notes, relationships and model limits
Practical tip
Change object location and move the screen to the real image. Lens and mirror send the outgoing light to opposite bench sides, even though their positive-distance equations share the same form.
Common trap
A virtual image cannot be collected just by placing a screen at its apparent position.
Model limits
Paraxial convex lens or concave mirror; screen distance is measured on the outgoing real-image side. Sharpness guide models defocus, not diffraction or aperture.
What you will learn
Distinguish projection and virtual-image observation.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
f20,d60 gives a real screen image at30 cm; d10 gives only a virtual image.
Why this matters
The model connects collect an image on a screen with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
A sharp projected image requires rays to?
- Only appear to meet
- Actually converge at the screen
- Remain parallel at every screen distance
Read the explanation
A screen receives actual converging light.
Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.