A spherical ball A of surface area $20 \mathrm{~cm}^{2}$ is kept at the centre of a hollow spherical shell B of area $80 \mathrm{~cm}^{2}$. The surface of $A$ and the inner surface of $B$ emit as blackbodies. Assume that the thermal conductivity of the material of $B$ is very poor and that of $A$ is very high and that the air between $A$ and $B$ has been pumped out. The heat capacities of $\mathrm{A}$ and $\mathrm{B}$ are $42 \mathrm{~J} /{ }^{\circ} \mathrm{C}$ and $82 \mathrm{~J} /{ }^{\circ} \mathrm{C}$ respectively. Initially, the temperature of $A$ is $100^{\circ} \mathrm{C}$ and that of $B$ is $20^{\circ} \mathrm{C}$. Find the rate of change of temperature of $A$ and that of $B$ at this instant. Explain the effects of the assumptions listed in the problem.
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All Study Material
- JEE Main
- Exam Pattern
- Previous Year Papers
- PYQ Chapterwise
- Physics
- Kinematics 1D
- Kinemetics 2D
- Friction
- Work, Power, Energy
- Centre of Mass and Collision
- Rotational Dynamics
- Gravitation
- Calorimetry
- Elasticity
- Thermal Expansion
- Heat Transfer
- Kinetic Theory of Gases
- Thermodynamics
- Simple Harmonic Motion
- Wave on String
- Sound waves
- Fluid Mechanics
- Electrostatics
- Current Electricity
- Capacitor
- Magnetism and Matter
- Electromagnetic Induction
- Atomic Structure
- Dual Nature of Matter
- Nuclear Physics
- Radioactivity
- Semiconductors
- Communication System
- Error in Measurement & instruments
- Alternating Current
- Electromagnetic Waves
- Wave Optics
- X-Rays
- All Subjects
- Physics
- Motion in a Plane
- Law of Motion
- Work, Energy and Power
- Systems of Particles and Rotational Motion
- Gravitation
- Mechanical Properties of Solids
- Mechanical Properties of Fluids
- Thermal Properties of matter
- Thermodynamics
- Kinetic Theory
- Oscillations
- Waves
- Electric Charge and Fields
- Electrostatic Potential and Capacitance
- Current Electricity
- Thermoelectric Effects of Electric Current
- Heating Effects of Electric Current
- Moving Charges and Magnetism
- Magnetism and Matter
- Electromagnetic Induction
- Alternating Current
- Electromagnetic Wave
- Ray Optics and Optical Instruments
- Wave Optics
- Dual Nature of Radiation and Matter
- Atoms
- Nuclei
- Semiconductor Electronics: Materials, Devices and Simple Circuits.
- Chemical Effects of Electric Current,