Physics

Thermal Properties and Thermodynamics

431 Questions

Thermal properties and thermodynamics questions evaluate concepts of heat transfer, thermal efficiency, and temperature variations. Problems involve calculating heat content, conductivity, and the performance of heat engines. This subject is regularly tested in physics sections across multiple competitive platforms.

Heat transfer calculationsThermal efficiencyBlack body radiationTemperature variationsRefrigeration performance

Thermal Properties and Thermodynamics Questions

Multiple choice physics isothermal and adiabatic processes work done by an ideal gas in isothermal expansion thermodynamic processes heat and thermodynamics

The slope of adiabatic curve is ________ than the slope of an isothermal curve.

  1. Greater.

  2. lesser

  3. data insufficient

  4. can be both a and b
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The slope of an adiabatic process is given by -gamma * P/V, while the slope of an isothermal process is -P/V. Since gamma (Cp/Cv) is always greater than 1 for an ideal gas, the adiabatic slope is steeper (greater in magnitude).

Multiple choice physics transfer of heat applications of heat conduction applications of insulation clothes - our necessity

Four rods of same material but with different radii and lengths are used to connect two reservoirs of heat with the same temperature difference. Which one will conduct more heat

  1. r=1 cm, 1=1 cm

  2. r=1 cm, 1= 2 cm
  3. r= 1 cm, $1=\frac{1}{2}m$
  4. $r=\frac{1}{2}cm$, $1=\frac{1}{2}m$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Heat conduction rate H = k*A*(delta T)/L. Since material and delta T are constant, H is proportional to A/L, or (r^2)/L. Calculating r^2/L for each: A) 1/1=1, B) 1/2=0.5, C) 1/0.5=2, D) 0.25/0.5=0.5. Option C gives the highest value.

Multiple choice physics transfer of heat applications of heat conduction applications of insulation clothes - our necessity

In a steady state of thermal conduction, temperature of the ends $A$ and $B$ of a $20cm$ long rod are $100^oC$ and $0^oC$, respectively. What will be the temperature of the rod at a distance of $6cm$ from the end $A$ of the rod?

  1. $-30^oC$
  2. $70^oC$
  3. $5^oC$

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

In steady state, the temperature gradient is linear. Temperature T(x) = T_A - (T_A - T_B) * (x / L). T(6) = 100 - (100 - 0) * (6 / 20) = 100 - 100 * 0.3 = 100 - 30 = 70 degrees Celsius.

Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

The following three objects (1) a metal tray, (2) a block of wood,and (3) a wooden cap are left in a closed room overnight. Next day the temperature of each is recorded as $T _1, T _2$ and $T _3$ respectively. The likely situation is 

  1. $ T _1 = T _2 = T _3 $
  2. $ T _3 > T _2 > T _1 $
  3. $ T _3 = T _2 > T _1 $
  4. $ T _3 > T _2 = T _1 $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All three will be inthermal equilibrium with air of room. so temprature of the three will be same

Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

An iron ball at $40^oC$ is dropped in a mug containing water at $40^o$C.

The heat will

  1. flow from iron ball to water

  2. not flow from iron ball to water or from water to iron ball.

  3. flow from water to iron ball.

  4. increase the temperature of both.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Thermal Equilibrium - A system is said to be in thermal equilibrium when there is no temperature difference between system and surroundings.

An iron ball at $40^oC$ is dropped in a mug containing water at $40^oC.$

The heat will not flow from iron ball to water or from water to iron ball.

Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

A piece of lead falls from height of $100m$ on a fixed non-conducting slab which brings it to rest. if the specific heat of lead is $30.6 cal/kg ^ \circ C $ the increase in temperature of the slab immediately after collision is  

  1. ${6.72^ \circ }C$
  2. ${7.62^ \circ }C$
  3. ${5.62^ \circ }C$
  4. ${8.72^ \circ }C$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Potential energy lost (mgh) is converted into heat (ms deltaT). Using g = 9.8 m/s^2, mgh = m * 30.6 * 4.184 * deltaT (converting cal to Joules). The mass cancels out, leading to deltaT = (9.8 * 100) / (30.6 * 4.184) approx 7.65 C.

Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

Two identical rods of a mental are welded in series then 20 cal of heat flows through them in  4 minute. If the rods are welded in parallel then same amount of heat will flow in 

  1. 1 minute

  2. 2 minute

  3. 4 minute

  4. 15 minute
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$dq/dt = [(AK)/2x][T2-T1] = 20/4 = 5.$

 $Therefore ( AK/x)(T2-T1) = 10$

When they are one above the other,

$dq/dt = 2Ak/x][T2-T1] =20/t$

Therefore$t = 2\times10  = 20/t$

Therefore$ t = 1 min$

Multiple choice solid waste management environmental management biology

Incineration is performed at

  1. High temperature more than 1000$^o$ C

  2. 273K
  3. Temperature lower than 200$^o$ C
  4. 0$^o$ C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Incineration is a waste treatment process that involves the combustion of organic substances contained in waste materials at very high temperatures, typically above 1000 degrees Celsius.