Explanation

The energy extracted from the vaporised liquid as evaporation occurs will decrease the temperature of the liquid, resulting in a process known as evaporative cooling.

Explanation

Head is the change in water levels between the hydro intake and the hydro discharge point.

It is a vertical height measured in metres.

Explanation

The third edition of the popular Structural and Stress Analysis provides the reader with a comprehensive introduction to all types of structural and stress analysis.

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Explanation

The center of gravity of an object is where we can consider all of the weight of the object to be concentrated.

This is a useful concept in physics and engineering.

Explanation

Water conservation is the practice of using water efficiently to reduce waste and preserve this precious resource.

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Explanation

Concrete drying is a continuous and fluid event, and usually reaches its full effective strength after about 28 days.

Explanation

The troposphere is the lowest layer of Earth's atmosphere.

Most of the mass of the atmosphere is in the troposphere.

Most types of clouds are found in the troposphere, and almost all weather occurs within this layer.

Major layers are 

troposphere

stratosphere

mesosphere

thermosphere 

exosphere

Explanation

Photo resistors  are light sensitive variable resistors 

فوٹو ریزسٹرز روشنی کے حساس متغیر ریزسٹرس ہیں۔

Explanation

The minimum voltage which can flow current in the human body is 70 to 80 volts

 کم از کم وولٹیج جو انسانی جسم میں کرنٹ بہا سکتا ہے 70 سے 80 وولٹ ہے

Explanation

A balloon is filled with a gas called helium.

while

A balloon filled with hydrogen gas moves in the upward direction