Select Question Set:
Q. No.The temperature at which the Celsius and Fahrenheit thermometers agree (to give the same numerical value) is:
| 1. | \(-40^\circ\) | 2. | \(40^\circ\) |
| 3. | \(0^\circ\) | 4. | \(50^\circ\) |
Subtopic: Temperature and Heat |
86%
Level 1: 80%+
Hints
Two rods \(A\) and \(B\) having the same length of \(1\) m are at the same temperature \(30^\circ \text{C}.\) The coefficients of linear expansion of \(A\) and \(B\) are in the ratio \(4:3.\) At what temperature will the length of \(B\) be the same as the length of rod \(A\) at \(180^\circ \text{C}\)?
| 1. | \(200^\circ \text{C}\) | 2. | \(230^\circ \text{C}\) |
| 3. | \(250^\circ \text{C}\) | 4. | \(270^\circ \text{C}\) |
Subtopic: Thermal Expansion |
78%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
The pressure that needs to be applied to the ends of a steel wire of length \(20~\text{cm}\) and area of cross-section \(0.5~\text m^2\) to keep its length constant when the temperature is raised by \(200^\circ \text{C}\) is:
(Young's modulus of elasticity \((Y)\) for steel is \(2\times10^{11}\) N/m2 and the coefficient of thermal expansion \((\alpha)\) is \(1.1\times10^{-5}~\text{K}^{-1})\)
(Young's modulus of elasticity \((Y)\) for steel is \(2\times10^{11}\) N/m2 and the coefficient of thermal expansion \((\alpha)\) is \(1.1\times10^{-5}~\text{K}^{-1})\)
| 1. | \(3.2 \times 10^6~\text{Pa}\) | 2. | \(2.2 \times 10^8~\text{Pa}\) |
| 3. | \(4.4 \times 10^8~\text{Pa}\) | 4. | \(2.2 \times 10^9~\text{Pa}\) |
Subtopic: Thermal Stress |
74%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
In a steel factory, it is found that to maintain \(M\) kg of iron in the molten state at its melting point, an input power \(P\) watt is required. When the power source is turned off, the sample completely solidifies in time \(t\) seconds. The latent heat of the fusion of iron is:
| 1. | \(\dfrac{2Pt}{M}\) | 2. | \(\dfrac{Pt}{2M}\) |
| 3. | \(\dfrac{Pt}{M}\) | 4. | \(\dfrac{PM}{t}\) |
Subtopic: Calorimetry |
83%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
In the Arctic region, hemispherical houses called Igloos are made of ice. It is possible to maintain a temperature inside an Igloo as high as \(20^\circ \text{C}\) because:
| 1. | ice has a high thermal conductivity. |
| 2. | ice has low thermal conductivity. |
| 3. | ice has a high specific heat. |
| 4. | ice has a higher density than water. |
Subtopic: Conduction |
66%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
Given below are two statements:
| Assertion (A): | In a pressure cooker the water is brought to a boil. The cooker is then removed from the stove. Now on removing the lid of the pressure cooker, the water starts boiling again. |
| Reason (R): | The impurities in water bring down its boiling point. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
Subtopic: Calorimetry |
50%
Level 3: 35%-60%
Hints
The radius of a spherical black body is \(R,\) and \(\alpha\) represents the rate of energy production within the body. The temperature of the given black body in a steady-state is: (where \(\sigma\) is Stefan- Boltzmann constant)
| 1. | \(\left(\dfrac{\alpha}{\sigma \times 4 \pi R^2}\right)^{\dfrac{1}{4}} \) | 2. | \(\left(\dfrac{\sigma \times 4 \pi R^2}{\alpha}\right)^{\dfrac{1}{4}}\) |
| 3. | \(\left(\dfrac{\alpha}{\sigma \times 4 \pi R^2}\right)\) | 4. | \(\left(\dfrac{4 \pi R^2 \times \sigma}{\alpha}\right)\) |
Subtopic: Stefan-Boltzmann Law |
80%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Two bodies \(A\) and \(B\) have emissivities of \(e_{A}\) and \(e_{B}\) respectively. The outer surface areas of two bodies are equal. The two bodies emit total radiant power at the same rate. The ratio of wavelength of \(B\) corresponding to maximum spectral radiancy to that of wavelength of \(A\) corresponding to maximum spectral radiancy is:
| 1. | \(\left(\dfrac{e_B}{e_A}\right)^4\) | 2. | \(\left(\dfrac{e_A}{e_B}\right)^{1\over 2}\) |
| 3. | \(\left(\dfrac{e_B}{e_A}\right)^{1\over 4}\) | 4. | \(\left(\dfrac{e_A}{e_B}\right)^{1\over 4}\) |
Subtopic: Wien's Displacement Law |
57%
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.
A radiation blackbody has the shape of a sphere of radius \(r.\) Its surface is at a temperature \(T\) (in Kelvin). If the temperature is doubled and the radius is halved, the total rate of radiation emitted from the body:
| 1. | increases by a factor of \(4\) |
| 2. | increases by a factor of \(2\) |
| 3. | remains unchanged |
| 4. | decreases by a factor of \(2\) |
Subtopic: Stefan-Boltzmann Law |
82%
Level 1: 80%+
Hints
A pan filled with hot food cools from \(95^\circ \text{C}\) to \(85^\circ \text{C}\) in \(2\) min when the room temperature is \(20^\circ \text{C}.\) The time taken by the food to cool from \(55^\circ \text{C}\) to \(45^\circ \text{C}\) will be:
| 1. | \(260\) s | 2. | \(280\) s |
| 3. | \(300\) s | 4. | \(320\) s |
Subtopic: Newton's Law of Cooling |
80%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Select Question Set:
© 2025 GoodEd Technologies Pvt. Ltd.