Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEET2002PhysicsThermal Properties of MatterActual

Which of the following is best close to an ideal black body?

Options

  1. ABlack lamp
  2. BCavity maintained at constant temperature
  3. CPlatinum black
  4. DA lamp of charcoal heated to high temperature

Correct answer

B. Cavity maintained at constant temperature

Step-by-step solution

An ideal black body is one which absorbs all the incident radiation without reflecting or transmitting any part of it. Black lamp absorbs approximately (96 % ) of incident radiation. An ideal black body can be realized in practice by a small hole in the wall of a hollow body (as shown in figure) which is at uniform temperature. Any radiation entering the hollow body through the holes suffers a number of reflections and ultimately gets completely absorbed. This can be facilitated by coating the interior surface with

Practice Thermal Properties of Matter on Quantrex Academy →

More from Thermal Properties of Matter

A cylindrical rod with one end in a steam chamber and the other end in ice results in melting of 0.1 gram of ice per second. If the rod is replaced by another with half the length 2026A spherical blackbody of radius 10 m is maintained at a temperature T , radiating power P with a peak emission wavelength 5000 Å . If the body is compressed uniformly such that its 2026The rectangular surface area (12 cm 6 cm ) of the black body, at a temperature 127^ C , emits heat energy at the rate of Q units per second. If the length and breadth of the surfac 2026A metal sphere cools at a rate of 2^ C/min when the temperature is 80^ C . If the temperature of the surroundings is 30^ C , then the rate of cooling when its temperature is 50^ C 2026A resistance thermometer has resistance 95 at the ice point and 140 at the steam point. The resistance obtained if the actual temperature is 30^ C is 2026A metal sphere cools from 80^ C to 60^ C in 10 minute. The time taken (in minute) by it to cool from 60^ C to 40^ C if the room temperature is 30^ C , is 2026If the temperature of 5 kg mass of a material of a specific heat capacity 200 J/kg ^ C rises from the 30^ C to 40^ C. The heat received is 2026The initial temperature of a body is 80^ C . If its temperature falls to 64^ C in 5 minutes and in the next 10 minutes to 52^ C , then the temperature of the surroundings is 2026 Full Thermal Properties of Matter list All NEET PYQs