Thermal Properties of Matter Test

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Thermal Properties of Matter Test - 41

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Weekly Quiz Competition

Question 1
1 / -0

When an inflated tyre bursts, the air escaping out __________.

A
will get heated up

B
will be cooled

C
will not undergo any change in its temperature

D
will be liquefied

Solution

Bursting of a tyre is an adiabatic expansive i.e, $$dQ=0$$ $$\&$$ $$dV=+ve$$
So, According to first law of thermodynamic $$dQ=dV+PdV$$
$$\Rightarrow -PdV=dV=CvdT$$
As $$P$$ is $$+ve$$ $$dV$$ is $$+V$$ thus $$dV=-ve$$
So, $$dT$$ is $$-ve$$ means decrease in temperature.
Hence, the answer is will be cooled.
Question 2
1 / -0

Two blocks of steel A and B, A being two times heavier than B, are at 40$$^o$$C. The ratio of heat content of A to B is:

A
1

B
4

C
2

D
$$\displaystyle \frac{1}{2}$$

Solution

Let the mass of block B be $$m$$.
So, mass of block A is $$2m$$
Both are made of steel, so, both has same specific heat capacity (let 'S')

So, $$\cfrac{Heat\;Capacity\;(A)}{Heat\;Capacity\;(B)}=\cfrac{2ms}{1ms}=2$$
Question 3
1 / -0

$$50 g$$ of ice at 0 C mixed with $$50 g$$ of water at 20 C. The final temperature of the mixture would be:

A
-30 C

B
-10 C

C
0 C

D
10 C

Solution

temperature will be zero as whole ice will not melt.
Question 4
1 / -0

The surface water in a lake is just going to freeze. What is the temperature of water at the bottom ?

A
$$0^{0}C$$

B
More than $$4^{0}C$$

C
$$4^{0}C$$

D
Less than $$4^{0}C$$

E
$$-2^{0}C$$

Solution

Correct Option is C.
Explanation for the correct answer:
$$\bullet$$ As water on the top surface of lake gets cooled, its density increases and the hot water which is less denser than cold water comes on the surface.
$$\bullet$$ But when temperature of water reaches $$4°C$$, further decrease in temperature decreases its density, and it remains on the top surface of the lake.
$$\bullet$$ Then temperature of top surface of water is further decreased and it is converted to ice at $$0°C$$, without affecting the water at the bottom of the lake. Thus temperature at the bottom of lake remains $$4°C$$.

Thus, if the surface of water in a lake is just going to freeze, then the temperature of water at the bottom is $$4°C$$.
Option C is correct.
Question 5
1 / -0

The figure shows that the level of water in the round bottom flask was initially at A. When heated the level fell to B and finally rises to C. Which of the following statements justify this observation

A
That's how all liquids behave

B
Anomalous expansion of water

C
The dissolved gases come out decreasing the volume

D
None of these

Solution

Anomalous expansion of water is its unique property. When water is cooled from room temperature it first contracts in volume and becomes increasingly dense as do other liquids, but at $$4^oC$$ water reaches its maximum density. On further cooling it starts expanding and becomes less dense. This will be continued till the temperature reaches $$0^oC$$, a point where it freezes into ice.
Question 6
1 / -0

State reason for unsolidification of water inside lakes in cold countries?

A
anomalous expansion of water

B
thermal conductivity of water

C
High specific heat capacity of water

D
Data insufficient

Solution

$$Answer:-$$ A
Firstly, let me give you a little basic knowledge about a property of liquids, then i'll proceed to the answer.

As the temperature of a liquid/solid increases, its volume increases. Most liquids behave this way. But, water has a unique quality, above (almost) 4°C water behaves normally i.e its volume increases as the temperature increases. However, between 0°C and almost 4°C its volume decreases with rise in temperature( or increases with temperature drop, thus making it less dense)-this is anomalous behaviour of water.

Say the water at the surface is at 12°C and its cooling down. Now, as the temperature decreases, its volume decreases and density increases. As the surface water reaches about 4°C, it becomes more dense and "sinks" to the bottom allowing the less dense water to surface up. As temperature falls below 4°C, surface water becomes lighter( less dense) compared to the water below and floats until it freezes. Once frozen, the ice insulates the water at the bottom from cooling so its temperature is maintained between 0 and almost 4°C, keeping it from freezing.
Question 7
1 / -0

We consider the radiation emitted by the human body. Which of the following statements if true?

A
The radiation is emitted during the summers and absorbed during the winters

B
The radiation emitted lies in the ultraviolet region and hence is not visible

C
The radiation emitted is in the infra-red region

D
The radiation is emitted only during the day

Solution

The heat radiation emitted by the human body is the infrared radiation. Their wavelength is of the order of $$7.9\times {10}^{-7}m$$ to $${10}^{-3}m$$ which is of course the range of infrared region.
Hence, human body emits radiation in infrared region.
Question 8
1 / -0

Newton's law of cooling holds good only, if the temperature difference between the body and the surroundings is

A
Less than $$10^{\circ} C$$

B
More than $$10^{\circ} C$$

C
Less than $$100^{\circ} C$$

D
More than $$100^{\circ} C$$

Solution

This is because the rate of loss of heat due to convection is proportional to the temperature difference for small temperature differences only. Hence Newton's law of cooling is derived assuming that the temperature difference is small.Hence , Newton's law of cooling holds good only, if the temperature difference between the body and the surroundings is less than $$10^oC$$ .
Question 9
1 / -0

When water cools below $$4^\circ{}$$ C, its volume

A
increases.

B
decreases.

C
remain constant.

D
Data insufficient

Solution

Answer is A
When water is cools below $$4^o$$C, its density decreases, hence volume increases.
Question 10
1 / -0

Heat travels through vacuum by:

A
convection

B
radiation

C
conduction

D
of all these

Solution

The process of convection and conduction requires some medium made of material particle for transmission of heat. In vacuum there is no material. So, heat travels in vacuum by radiation.

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Re-Attempt Weekly Quiz Competition

Thermal Properties of Matter Test - 41

Result

Thermal Properties of Matter Test - 41

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SHARING IS CARING

Question 1

will get heated up

will be cooled

will not undergo any change in its temperature

will be liquefied

Solution

Question 2

1

4

2

$$\displaystyle \frac{1}{2}$$

Solution

Question 3

-30 C

-10 C

0 C

10 C

Solution

Question 4

$$0^{0}C$$

More than $$4^{0}C$$

$$4^{0}C$$

Less than $$4^{0}C$$

$$-2^{0}C$$

Solution

Question 5

That's how all liquids behave

Anomalous expansion of water

The dissolved gases come out decreasing the volume

None of these

Solution

Question 6

anomalous expansion of water

thermal conductivity of water

High specific heat capacity of water

Data insufficient

Solution

Question 7

The radiation is emitted during the summers and absorbed during the winters

The radiation emitted lies in the ultraviolet region and hence is not visible

The radiation emitted is in the infra-red region

The radiation is emitted only during the day

Solution

Question 8

Less than $$10^{\circ} C$$

More than $$10^{\circ} C$$

Less than $$100^{\circ} C$$

More than $$100^{\circ} C$$

Solution

Question 9

increases.

decreases.

remain constant.

Data insufficient

Solution

Question 10

convection

radiation

conduction

of all these

Solution

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