#heat loss

Electric Current, Drift Velocity and Mobility

What is the primary source of energy dissipation in a resistor carrying current?

**Mobility** μ = v_d/E = e τ/m, τ relaxation time (s), measures ease of electron drift under field E (V/m). Conductivity σ = n e μ = 1/ρ, linking microscopic τ to macroscopic resistivity, explaining why metals conduct well due to large n and τ. Energy dissipation in a resistor occurs as electrons collide with lattice ions, transferring kinetic energy gained from the electric field into thermal energy (heat) via lattice vibrations. Applying I = n e A v_d, R = ρ l/A, R_t = R₀[1+αΔT], Kirchhoff's ΣI=0, ΣV=0, R_eq series/parallel, V = ε - I r and P = I²R, evaluation yields Collisions with

Ref: NCERT > Physics Book > Current Electricity > Electric Current, Drift Velocity and Mobility

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Specific Heat Capacity and Latent Heat

A system releases 600 J of heat and performs 250 J of work. What is the change in internal energy?

**Heat capacity** at constant pressure C_p and volume C_v, C_p = C_v + R per mole, for solids Dulong-Petit C_v≈3R≈25 J/mol·K. Specific heat and latent heat govern temperature changes and phase transitions, Q = m c ΔT for heating, Q = m L for melting/boiling at constant T. First Law: Δ Q = Δ U + Δ W . Δ Q = -600 J (heat released), Δ W = 250 J (work by system). -600 = Δ U + 250 ⇒ Δ U = -600 - 250 = -850 J . Using first law ΔU = Q - W, W = ∫ P dV, isobaric

Ref: NCERT > Physics Book > Thermodynamics > Specific Heat Capacity and Latent Heat

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Latent Heat and Phase Transitions

Why does a calorimeter use a material with low specific heat capacity for its container?

A material with low specific heat capacity absorbs less heat, minimizing its effect on the heat exchange between the substances being measured, ensuring accurate results. As per NCERT, applying relevant law/formula with correct units and sign convention leads to To absorb less heat. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Chapter 11: Thermal Properties – Calorimetry.

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Adaptation

Which factor determines faster heat loss in small animals?

Heat exchange occurs across body surface, while heat-producing tissue broadly scales with body volume or mass. As an animal becomes smaller, surface area decreases with the square of linear dimension but volume decreases with the cube. Small animals therefore have a high surface-area-to-volume ratio and lose heat rapidly per unit mass when their bodies are warmer than the environment. To maintain a stable temperature, small endotherms generally require high mass-specific metabolic rates, frequent feeding, insulation, or behaviours such as huddling and sheltering. High metabolic rate is mainly

Ref: Evolutionary Analysis, Herron & Freeman, 5th Ed., Ch. 10

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Ecosystem Efficiency and Decomposition

Which component of energy flow is lost as heat?

“Respiration” for which component of energy flow is lost as heat. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Ecosystem processes are constrained by energy conservation and by the cycling of matter. Energy enters mainly through primary production, is lost as metabolic heat at every transfer, and therefore cannot be recycled in the way that carbon, nitrogen, phosphorus, or water can. The remaining alternatives—“Assimilation”, “Production”, “Consumption”—refer to different states, processes, or

Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 3

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Thermoregulation

When heat production exceeds heat loss, body temperature will:

Answer: C) Increase. For Thermoregulation, once you lock onto the key mechanism or definition, Increase is the clear fit. If you restate the concept in your own words, Increase is the option that correctly names the structure, process, or principle asked for in Thermoregulation. So Increase is the clean, accurate selection. If a similar stem appears later, start from the same core fact and you will land on the same kind of answer. In class notes, highlight this same phrase next to the related diagram so the wording and the picture reinforce each other. When you practise, cover the choices firs

Ref: Animal physiology is Unit 7 of the CSIR NET Life Science Syllabus, covering core body systems. It accounts for roughly 10% of the total marks in Sections B and C.

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