Tag: internal energy

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Questions Related to internal energy

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

Define the term heat :

  1. the condition or quality of being hot

  2. the sensation of warmth or hotness

  3. the degree of hotness; temperature

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Heat is the transfer of kinetic energy from one medium or object to another. Such energy transfer can occur in three ways: radiation, conduction, and convection.

Also, it can be defined as the quality of being hot, high temperature, and degree of hotness and temperature.

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

In a sports meet the timing of a $200\ m$ straight dash is recorded at the finish point by starting an accurate stop watch on hearing the sound of starting gun fired at the starting point. The time recorded will be more accurate

  1. In winter

  2. In summer

  3. In all seasons

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

The velocity of sound is directly proportional to the square root of absolute temperature.
The formula for velocity of sound in a gas is
$v = \sqrt {\dfrac {\gamma p}{\rho}}$
According to standard gas equation
$pV = RT$
or $p = \dfrac {RT}{V}$
$\therefore v = \sqrt {\dfrac {\gamma RT}{\rho \times V}} = \sqrt {\dfrac {\gamma RT}{M}}$
where $\rho \times V = M$, the molecular weight of the gas
$\therefore v\propto \sqrt {T}$
Hence, the sound of the gun fired at the starting point will reach the finishing point quicker in summer than in winter. The lapse of time due to the time taken by the sound in reaching the finish point will be less in summer and, hence the time recorded will be more accurate in summer than in winter.

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

Two blocks of steel A and B of the same shape and size, A being two times heavier than B, are at $40^{\circ}C$. The ratio of heat content of A to B is

  1. $1$

  2. $4$

  3. $2$

  4. $\displaystyle\frac{1}{2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The correct answer is option(C).

We know,
$Q=mC\Delta T$
Here Specific heat and raise in temperatures are equal.
And, given $2m _A=m _B$
So, the ratio of heat content can be,
$\dfrac {Q _1}{Q _2}=\dfrac {m _AC\Delta T}{m _BC\Delta T}=\dfrac {m _A}{m _B}=\dfrac 21=2$

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

State whether given statement is True or False
Heat is an invisible form of energy, which causes the sensation of hotness or coldness.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

No body can see the exchange of heat or heat itself it is invisible and its effect or transfer can only be felt by the increases or decreases in temperature or the sensation of hotness and coldness.
Hence, OPTION : A (true).

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

According to law of conservation of energy, heat energy is transformed into which two types of energy?

  1. Kinetic and potential energy

  2. Mechanical and potential energy

  3. Kinetic and thermal energy

  4. Nuclear and potential energy
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to law of conservation of energy, heat energy is transformed into Kinetic and potential energy