Tag: change of states

Questions Related to change of states

The melting point of mercury is:

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. $38.8\ ^\circ C$

  2. $-38.8\ ^\circ C$

  3. $4250\ ^\circ C$

  4. $452\ ^\circ C$

Show answer
Correct Option: B
Explanation:

Melting point of mercury is $-38.83^oC$

Water at normal atmospheric pressure boils at :

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. $0^{\circ}C$

  2. $100^{\circ}C$

  3. $250\ K$

  4. $50^{\circ}C$

Show answer
Correct Option: B
Explanation:

Boiling occurs when the vapor pressure exceeds the surrounding pressure from the atmosphere. At standard atmospheric pressure, water boils at approximately $100^0 C$.

Boiling point of water at normal atmospheric pressure is ____________

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. ${0}^{o}C$

  2. ${100}^{o}C$

  3. ${110}^{o}C$

  4. ${-5}^{o}C$

Show answer
Correct Option: B
Explanation:

Boiling point of water at normal atmospheric pressure is $100^oC$

The temperature of boiling water in the Kelvin scale of temperature is:

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. $100$ K

  2. $373.15$ K

  3. $212$ K

  4. $273.15$ K

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Correct Option: B
Explanation:

The relation between Celsius and Kelvin is given by, $K = C + 273.15$

So, temperature of boiling water $=100^oC=100+273.15K=373.15K$

Cooking takes longest time

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. At the sealevel

  2. At Simla

  3. At Mount Everest

  4. In a submarine 100 m below the surface of water

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Correct Option: C

Normallly the body temperature of healthy person is ______ Degree celcius?

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. 25

  2. 37

  3. 30

  4. 32

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Correct Option: B
Explanation:
Normally the body temperature of healthy person is $37^oC$ or ($98.6^oF$)
It is scientific fact that normal body temperature of a healthy body is $37^oC$. Apparently it is the perfect balance as it's warm enough to prevent fungal infection but not so hot that we need to eat non-stop to maintain out metabolism.

Water in a lake is changing into ice at $0^{o}C$. When the atmospheric temperature is $10^{o}C$. If the time taken for $1\ cm$ thick ice layer to be formed is $7$ hour, the time required for the thickness of ice to increase from $1\ cm $ to $2\ cm$ is

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. $7\ hour$

  2. $14\ hour$

  3. $<7\ hour$

  4. $>14\ hour$

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Correct Option: B

25 degree celcius is equal to ?

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. 77 Fahrenheit

  2. 85 Fahrenheit

  3. 100 Fahrenheit

  4. 120 Fahrenheit

Show answer
Correct Option: A
Explanation:
For converting $^oC$ in $^oF$, we know by formula:
$F=\cfrac{9}{5}C+32$
For $25^oC$,
$F=\cfrac { 9 }{ 5 } \times 25+32=45+32=77℉\\ 25℃=77℉$

How much heat energy is gained when 5 kg of water at  $20 ^ { \circ } \mathrm { C }$ is brought to its boiling point?

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. 1680 KJ

  2. 1700 KJ

  3. 1720 KJ

  4. 1740 KJ

Show answer
Correct Option: A
Explanation:

$Q = mc\Delta \theta $

$ = 5 \times \left( {1000 \times 4.2} \right) \times \left( {100 - 20} \right)$
$ = 1680 \times {10^3}J$
$ = 1680\,KJ$
Hence,
option $(A)$ is correct answer.

The melting point and the boiling point of oxygen is:

physics the kinetic model of matter force and kinetic theory change of states phase change

  1. negative

  2. positive

  3. zero

  4. none of these

Show answer
Correct Option: A