Tag: chemistry

Questions Related to chemistry

The acid generally stored in batteries is :

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. sulphuric acid

  2. nitric acid

  3. hydrochloric acid

  4. acetic acid

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Correct Option: A
Explanation:

Sulphuric acid develops voltage from the chemical reaction produced when two unlike materials such as the positive and negative plates are immersed in the electrolyte a solution of sulphuric acid and water. In typical lead-acid battery the voltage is approx. 2 volts per cell for a total of 12 volts.

Soda-acid fire extinguisher extinguishes the fire by :

reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

  1. cutting the supply of air

  2. removing the combustible substance

  3. raising the ignition temperature

  4. none of these

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Correct Option: A
Explanation:
The principle of working of fire extinguisher is based on either of the following three conditions: 
• cooling the combustible material below its ignition temperature, or 
• cutting off the supply of air, or 
• cooling the combustible material and at the same time cutting the supply of air. 

Which of the following statements is incorrect?

chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

  1. When a material is under tensile stress, the restoring forces are caused by interatomic attraction while under compressional stress, the restoring force is due to interatomic repulsion

  2. The stretching of a coil is determined by its shear modulus

  3. Rubber is more elastic than steel

  4. Shearing stress plays an important role in the buckling of shafts

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Correct Option: C
Explanation:

More elastic means, the value of an elastic constant is more and. Steel have move elastic constant in compare to Rubber, So Steel is more elastic than rubber.
All other statements are correct.

Out of the following whose elasticity is independent of temperature

chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

  1. steel

  2. copper

  3. Invar steel

  4. glass

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Correct Option: C
Explanation:

For most of the materials, elasticity decreases with temperature. One exception is invar steel.

Fill in the blank.
In a technical sense a substance with a ________ elasticity is one that requires a ______  force to produce a distortion-for example, a steel sphere. 

chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

  1. high, small

  2. high, large

  3. low, large

  4. low , small

Show answer
Correct Option: B
Explanation:

According to Hooke's law, within elastic limit,

    $E=\dfrac{stress}{strain}$$=\dfrac{deforming\ force}{(area\times strain)}$ 
It means higher the elasticity, larger will be the required deforming force.
Hence, in a technical sense a substance with a high elasticity is one that requires a high force to produce a distortion.

As compared to concrete, steel has compressive strength:

chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

  1. $25$ times less

  2. equal

  3. $25$ times more

  4. $5$ times more

Show answer
Correct Option: C
Explanation:

Compressive strength is the capacity of a material or structure to withstand loads tending to reduce size, as opposed to tensile strength, which withstands loads tending to elongate.

Compressive strength is one of the most important engineering property of Concrete which designers are concerned of. However the compressive strength of steel is around 25 time more than that of concrete.

Elasticity is defined as the ability of a body to 

chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

  1. Resist linear motion in a hard surface

  2. Resist rolling motion in a hard surface

  3. Resist a distorting influence and to return to its original size and shape when that influence or force is removed.

  4. Resist electric current in a magnetic field

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Correct Option: C
Explanation:

Elasticity is defined as the ability of a body to  resist a distorting influence and to return to its original size and shape when that influence or force is removed.

Substances that elongate considerably and undergo plastic deformation before they break are known as

chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

  1. brittle substances

  2. breakable substances

  3. ductile substances

  4. all of these

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Correct Option: C
Explanation:

Substances that elongate considerably and undergo plastic deformation before they break are known as ductile substances

Substances that break just after elastic limit is reached are known as 

chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

  1. brittle substances

  2. breakable substances

  3. ductile substances

  4. elastic substances

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Correct Option: A
Explanation:

Substances that break just after elastic limit is reached are known as brittle substances

An elastic metal rod will change its length when it

chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

  1. falls vertically under its weight

  2. is pulled along its lengthy by a force acting at one end

  3. both

  4. none

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Correct Option: B