science

Pahar

Pahar is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pahar rather than just read about it. In short: Pahar (Bengali পহর, Hindi/Nepali: पहर, Punjabi: ਪੈਹਰ, Urdu: پہر), which is more commonly pronounced peher (/pɛhɛr/) is a traditional unit of time used in India, Pakistan, and Bangladesh. One pahar nominally equals three hours, and there are eight pahars in a day.

Key takeaways

Pahar belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pahar to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pahar from memory before moving on to harder problems.

Reference excerpt

Pahar (Bengali পহর, Hindi/Nepali: पहर, Punjabi: ਪੈਹਰ, Urdu: پہر), which is more commonly pronounced peher (/pɛhɛr/) is a traditional unit of time used in India, Pakistan, and Bangladesh. One pahar nominally equals three hours, and there are eight pahars in a day. In India, the measure is primarily used in North India and by Hindi-speaking communities throughout the Deccan in Southern India.

Etymology Pahar/pehar/peher is derived from Sanskrit word prahar which is an ancient unit of time in India. The word pahar/peher has the same root as the Hindustani word pehra (meaning "to stand guard") and pehredar (literally "guard/watchman"). It literally means a "watch" (i.e. period of guard-duty).

Timing Traditionally, night and day were each allocated four pahars, or "watches." The first pahar of the day (or din pahar) was timed to begin at sunrise, and the first pahar of the night (raat pahar) was timed to begin at sunset. This meant that in the winter the daytime pahars were shorter than the nighttime pahars, and the opposite was true in summer. The pahars were exactly equal on the equinoxes. Thus, the length of the traditional pahar varied from about 2.5 hours to 3.5 hours in the Indo-Gangetic plains. Each pahar of a 24-hour day-night cycle has a specific name and number. The first pahar of the day, known as pehla pahar (Hindustani: pehla, lit. 'first'), corresponds to the early morning and sunrise. The second pahar is called do-pahar (Hindustani: do, lit. 'second'). However, in the common speech of North India, Pakistan and Nepal, dopahar (दोपहर or دوپہر) has now come to be known as the generic term for afternoon or the time after midday, since it begins after completing the do-pahars. The third pahar is called seh pahar (Persian: seh, lit. 'three') and has generically come to mean evening, though the term is less commonly used than shaam.

Literature The poet-saint Kabir mentions pahar in one of his dohas:

[You] went to work for five pahars, slept for the remaining three pahars. How will you attain salvation without chanting the names of Lord Hari for at least one pahar?

References

Worked examples

Example 1 — a first encounter with Pahar

Start with the simplest possible case. Write down what Pahar claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pahar before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pahar ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pahar

In research: Pahar appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pahar in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pahar is common in secondary-school and first-year university syllabi. It links to neighbouring topics Culture of India, Culture of Pakistan, Units of time, so understanding it makes those chapters shorter.
In everyday life: Look for Pahar outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pahar in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pahar means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pahar out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pahar in simple terms?

Why does Pahar matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pahar?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pahar.