Please select a subject first
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Answer the following question.
Derive its expression for the coefficient of thermal conductivity.
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Answer the following question.
Give any four applications of thermal conductivity in everyday life.
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Answer the following question.
Explain the term thermal resistance. State its SI unit and dimensions.
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Answer the following question.
How heat transfer occurs through radiation in absence of a medium?
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Answer the following question.
Which materials can be used as thermal insulators and why?
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Solve the following problem.
Which will require more energy, heating a 2.0 kg block of lead by 30 K or heating a 4.0 kg block of copper by 5 K?
(slead = 128 J kg–1 K–1, `"s"_"copper"` = 387 J kg–1 K–1)
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Solve the following problem.
The rate of flow of heat through a copper rod with temperature difference 30 °C is 1500 cal/s. Find the thermal resistance of copper rod.
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Solve the following problem.
An electric kettle takes 20 minutes to heat a certain quantity of water from 0 °C to boiling point. It requires 90 minutes to turn all the water at 100 °C into steam. Find the latent heat of vaporization. (Specific heat of water = 1 cal/g °C)
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Solve the following problem.
Find the temperature difference between two sides of a steel plate 4 cm thick, when the heat is transmitted through the plate at the rate of 400 k cal per minute per square meter at a steady state. Thermal conductivity of steel is 0.026 kcal/m s K.
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Explain balancing or mechanical equilibrium. The linear velocity of a rotating fan as a whole is generally zero. Is it in mechanical equilibrium? Justify your answer.
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Solve the following problem.
A 2 m long wooden plank of mass 20 kg is pivoted (supported from below) at 0.5 m from either end. A person of mass 40 kg starts walking from one of these pivots to the farther end. How far can the person walk before the plank topples?
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Solve the following problem.
A 2 m long ladder of mass 10 kg is kept against a wall such that its base is 1.2 m away from the wall. The wall is smooth but the ground is rough. The roughness of the ground is such that it offers a maximum horizontal resistive force (for sliding motion) half that of normal reaction at the point of contact. A monkey of mass 20 kg starts climbing the ladder. How far can it climb along the ladder? How much is the horizontal reaction at the wall?
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The distance between two bodies is doubled. How is the magnitude of the gravitational force between them affected?
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Answer the following question.
Why do we need to know the center of mass of an object? For which objects, its position may differ from that of the center of gravity?
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Answer the following question.
State Newton’s law of cooling and explain how it can be experimentally verified.
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Solve the following problem.
A metal sphere cools at the rate of 0.05 ºC/s when its temperature is 70 ºC and at the rate of 0.025 ºC/s when its temperature is 50 ºC. Determine the temperature of the surroundings and find the rate of cooling when the temperature of the metal sphere is 40 ºC.
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A metal sphere cools from 80 °C to 60 °C in 6 min. How much time with it take to cool from 60 °C to 40 °C if the room temperature is 30 °C?
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Match the following pairs.
| A | B | ||
| 1. | Tri-doshas | a) | First laboratory of psychology |
| 2. | Tri-gunas | b) | Study of unconscious |
| 3. | Wilhelm Wundt | c) | Perception, thinking, memory etc |
| 4. | Sigmund Freud | d) | Satva, Rajas, Tamas |
| 5. | Cognitive processes | e) | Ashtanga Yog |
| 6. | Patanjali | f) | Kapha, Vaat and Pitta |
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Match the following pairs.
| A | B | ||
| 1. | Tri-doshas | a) | First laboratory of psychology |
| 2. | Tri-gunas | b) | Study of unconscious |
| 3. | Wilhelm Wundt | c) | Perception, thinking, memory etc |
| 4. | Sigmund Freud | d) | Satva, Rajas, Tamas |
| 5. | Cognitive processes | e) | Ashtanga Yog |
| 6. | Patanjali | f) | Kapha, Vaat and Pitta |
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Match the following pairs.
| A | B |
| 1) Tri-doshas | a) First laboratory of psychology |
| 2) Tri-gunas | b) Study of unconscious |
| 3) Wilhelm Wundt | c) Perception, thinking, memory etc |
| 4) Sigmund Freud | d) Satva, Rajas, Tamas |
| 5) Cognitive processes | e) Ashtanga Yog |
| 6) Patanjali | f) Kapha, Vaat and Pitta |
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