Receiver questions
● VERBATIM — examined word-for-wordPower collected = I at that point × receiver area (perpendicular). Detector size changes the power collected, never the intensity there. Energy received = I × A × t. Two routes to I at a receiver: P_source/4πr² or P_received/A_receiver — use whichever pair the question supplies. Convert cm² → m² religiously.
P_received = I × A_receiverWhat this actually means
Two-step logic every time: find the intensity at the receiver's location, then multiply by the receiver's perpendicular area to get power collected. Multiply by time for energy.
A bigger detector catches more power, but the intensity at that spot is a property of the location, not of the instrument sitting there.
There are two independent routes to I: from the source side (P/4πr²) or from the receiver side (P_received/A_receiver). Use whichever pair of numbers the question hands you, and convert cm² to m² before touching anything.
Claiming a larger detector raises the intensity — it only raises the power collected.
Prove it — watch it be true
- Fix the detector distance and read I
- Press area ×2: power collected doubles, I readout unchanged
- Press r ×2 instead: now I itself falls — location changed, not instrument