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1 Markets I: The Ecosystem and Exchange-Traded Marketsবাজার অনলাইন 2 Markets II: Rates, FX and Creditবাজার অনলাইন 3 Markets III: Commodities, Energy and Cryptoবাজার অনলাইন 4 Quantitative Methodsপদ্ধতি অনলাইন 5 Derivatives and Volatilityডেরিভেটিভস অনলাইন 6 Rates, Credit, XVA and Riskসুদহার, ঋণ ও ঝুঁকি অনলাইন 7 Research Craft: Predictors, Backtests, Measurement, Portfoliosগবেষণা অনলাইন 8 Strategies I: Equities and Futuresকৌশল অনলাইন 9 Strategies II: Volatility, Relative Value, Macro and the Bank Desksকৌশল অনলাইন 10 Microstructure and Executionএক্সিকিউশন অনলাইন 11 Market Making and High-Frequency Tradingমার্কেট মেকিং অনলাইন 12 Machine Learning for Marketsমেশিন লার্নিং অনলাইন 13 Low-Latency Softwareপ্রযুক্তি অনলাইন 14 Networks, Hardware and Trading Infrastructureপ্রযুক্তি অনলাইন 15 Research, Data and Risk Platformsপ্রযুক্তি অনলাইন 16 The Desk and the Firmপ্রতিষ্ঠান অনলাইন 17 The Industry: Firms, Roles and Careersক্যারিয়ার অনলাইন 18 Interviews I: Maths, Probability and Speedক্যারিয়ার অনলাইন 19 Interviews II: Markets, Trading Games and the Final Roundক্যারিয়ার অনলাইন 20 Interviews III: Codeক্যারিয়ার অনলাইন
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Physics · পরিভাষা

Phases কী?

অন্য নাম: phase · waxing · waning

Definition 51.2 Primary & Middle School Physics · অধ্যায় 51 — Phases of the Moon

The phases of the Moon are its apparent shapes through the month: new moon (day side turned fully away — we see nothing), crescent, first quarter (half the disc lit), gibbous (more than half), full moon (day side turned fully toward us), then gibbous, last quarter and crescent again, closing the cycle in about 29.529.5 days. From new to full the lit part grows night by night: the Moon is waxing; from full back to new it shrinks: waning.

The whole secret in one picture: eight stations of the orbiting Moon, each half-lit on its sunward side. What changes is only which slice of the day side faces the Earth.
The whole secret in one picture: eight stations of the orbiting Moon, each half-lit on its sunward side. What changes is only which slice of the day side faces the Earth.

উদাহরণ

Example 51.5 (Eclipse versus phase)

Keep the two Moon-darkenings in separate drawers. Phase: the slow monthly cycle, the Moon’s own night side turning toward us — no shadow of ours involved. Lunar eclipse: a rare hour when the full Moon crosses our umbra — the Earth’s shadow genuinely falling on it, coppery and swift. The diary’s rhythm is a view; the eclipse is a visit.

Example 51.6 (Where the phases keep their hours)

The diagram fixes each phase to a position — and each position to a schedule. The full Moon stands opposite the Sun: it must rise at sunset, reign all night, and set at sunrise. The new Moon travels with the Sun: up all day, lost in glare — which is why nobody “sees” a new moon. First quarter trails the Sun by a quarter turn: it rises near midday and sets near midnight — the after-dinner Moon. The old daytime-Moon surprise of your childhood is now a timetable: any Moon not new nor full shares part of its shift with the Sun.

Example 51.7 (Which way does the crescent point?)

The lit side of any phase faces the Sun — the crescent is a bow aimed at its archer. Evening crescent in the west: horns pointing up-and-away from the sunset glow beneath the horizon. The sky never draws it wrong; painters often do. A crescent with its horns toward the Sun is astronomy’s favorite spot-the-error.

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