Tag: measuring thermal quantities by the method of mixtures

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Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

When in thermal contact, the quantity of heat lost by the hotter body is ...... the amount of heat gained by the colder body. (neglect loss of heat due to convection & radiation)

  1. Equal to

  2. Greater than

  3. Less than

  4. Cannot say
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
When in thermal contact, the quantity of heat lost by the hotter body is equal to the amount of heat gained by the colder body. (neglect loss of heat due to convection & radiation)
This is the principle of calorimetry.
Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

Bunty mixed 440 gm of ice at $0^{\circ}C$ with 540 gm of water at $80^{\circ} C$ in a bowl. Then what would remain after sometime in the bowl?

  1. only ice

  2. only water

  3. ice and water in same amount

  4. ice and water will vapourise
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Energy for ice= mL=440(336)= 147840 J
Energy in water= mc$\theta$= 540(80)(4.2)= 181440J

Since, water has more energy, the ice will completely melt while the temperature of water will decrease.
so only ice remains.

Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

The quantity/ quantities that does/do not have mass in its/their dimensions is/are

  1. Specific heat

  2. Latent heat

  3. Electrical potential difference

  4. Electrical resistance
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation

Specific heat- $J/kg^oC$
Latent Heat- J/kg
Electrical potential difference- J/coulumb
Electrical resistance- ohm
 Hence, option C and D are correct

Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

When 60 calories of heat are supplied to 15 g of water, the rise in temperature is

  1. <font><font>$75^{\circ}C$</font></font>

  2. <font><font>$90^{\circ}C$</font></font>

  3. <font><font>$4^{\circ}C $</font></font>

  4. <font><font>$0.25^{\circ}C$</font></font>
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$Heat = m S \Delta T$
$\Rightarrow 60=15\times 1\times\triangle T \ \Rightarrow \triangle T=4^oC$

Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

Calorimeters are generally made of

  1. copper

  2. brass

  3. aluminium

  4. zinc
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Calorimeters is made of copper because:
1) Copper has low specific heat capacity and thus it reaches equilibrium temperature quickly by absorbing small amount of heat.

2) Cu is highly malleable and hence very thin box of small mass can be made, thus decreasing heat capacity of box.

3) Cu is good conductor of heat.
Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

On which law does the study of calorimetry based?

  1. Joule's law

  2. Law of conservation of energy

  3. Law of Kinetic energy

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Principle of calorimetry states that heat lost by a hotter body = heat gained by a colder body, therefore in calorimetry, total heat energy of the system remains constant, which is the law of conservation of energy . 

Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

When 60 calories of heat are supplied to 15 g of water, the rise in temperature is

  1. $75^\circ C$

  2. $900^\circ C$

  3. $4^\circ C$

  4. $0.25^\circ C$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

We know that, $heat=mass\times specific \;heat\times change\;in\;temperature \ \Rightarrow 60=15\times 1\times \triangle T \ \Rightarrow \triangle T=4^oC$

Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

A thermos bottle containing coffee is vigorously shaken. If the coffee is considered as a system, then the temperature of the coffee will 

  1. increase slightly

  2. fall

  3. remain the same

  4. never be determined
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A thermoflask is closed system, so no heat energy added to system i.e. $\triangle \theta=0$
Work is done on the system by shaking it against viscous force. Hence $\triangle w=-ve$
Internal energy, $\triangle U=\triangle \theta - \triangle w=0-(-\triangle w) \\ \Rightarrow \triangle U=+\triangle w$
$\because \triangle U\; is\; +ve$ So there is increase in temperature due to rise in internal enrgy.
Multiple choice physics measurement and effects of heat heat exchange calorimeter measuring thermal quantities by the method of mixtures

The branch of physics that deals with the measurement of heat energy is known as

  1. Fermentation

  2. Latent heat

  3. Calorimetry

  4. Hidden heat
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Calorimetry is the branch of physics which deals with the measurement of heat energy. Calorimetry is one of the methods for the determination of specific heats or latent heats of the substances.