Answer key

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Last edited 26 days ago by Learn LoopHQ.

Chapter: 03. Physical Quantities And Measurement 2

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Answer Key - Answer in One Line

The average pulse rate of students in a class is calculated by adding the pulse rates of all the students and dividing the sum by the total number of students.

Caesium is a soft silvery metal used in the most accurate atomic clocks because it provides stable vibrations necessary for precise time measurement.

The main purpose of measuring time accurately is to schedule and coordinate our daily activities effectively.

Mercury appears as a shiny thread in a thermometer’s capillary tube because of its metallic and reflective properties, making it easily visible for reading.

The straw in a sundial is slanted towards the ‘12’ line at noon to align it with the Earth’s axis, ensuring that its shadow accurately indicates the time as the sun moves across the sky.

Heat transfer can only take place when there is a difference in temperature between the two bodies.

Greenwich Mean Time (GMT) is the local time at Greenwich, from where the Prime Meridian passes, and it is used as a global reference point for measuring time.

It is mandatory to mention a.m. or p.m. in the 12-hour clock convention to indicate whether the time is before or after midday.

A constriction in a clinical thermometer helps by preventing the mercury level from falling back into the bulb immediately after the thermometer is removed, allowing time for an accurate reading.

Three early instruments used to measure time include the water clock, candle clock, and sand clock.

A laboratory thermometer is primarily used to measure room temperature or the temperature of solids and liquids in a laboratory setting.

Heat is a form of energy related to the motion of constituent particles, while temperature is the degree of hotness or coldness of a body.

Time is defined as the interval between two events.

When measuring pulse rate at the wrist, each pulse represents one heartbeat.

The typical temperature range of a clinical thermometer is from 35° C to 42° C (or 95° F to 108° F).

If a mercury thermometer breaks, it should not be thrown directly into the dustbin due to mercury’s harmful nature, and its disposal should follow specific guidelines for chemical waste.

Daniel Gabriel Fahrenheit invented the first modern mercury thermometer with a standardized scale.

Heat transfer takes place from a body with a higher temperature to a body with a lower temperature.

Jantar Mantar contains architectural astronomy instruments such as the Samrat Yantra, which are large sundials designed to accurately predict time and observe celestial movements.

Your pulse rate usually increases after physical activity like hopping because your body needs more oxygen and nutrients, so your heart beats faster to pump more blood to your muscles.

To convert a time greater than 1200 hours from 24-hour format to 12-hour format, you subtract 1200 from the 24-hour format time and add “p.m.”.

Two other commonly used units of temperature are degree Celsius (°C) and degree Fahrenheit (°F).

It is important to place your eye at the level of the mercury when reading a thermometer to avoid parallax error, which occurs when viewing from an angle and leads to an inaccurate reading.

The primary purpose of the International System of Measurement is to provide a standardized unit of measurement globally for consistency in science, industry, and commerce.

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