Title QM DPP Sheet 03.pdf ✅

1 North Delhi : 56-58, First Floor, Mall Road, G.T.B. Nagar (Near Metro Gate No. 3), Delhi-09, Ph: 011-41420035 South Delhi : 28-A/11, Jia Sarai, Near-IIT Metro Station, New Delhi-16, Ph : 011-26851008, 26861009 IIT JAM PHYSICS 2024 (Online Batch) Section: MODERN PHYSICS (Quantum Mechanics) Chapter: BLACK BODY RADIATION Daily Practice Problem (DPP) Sheet 3 PART I: Multiple Choice Questions (MCQ) 1. When the temperature of a blackbody is made 3 times, the total intensity of radiation with respect to that at initial temperature, would become (a) 9 times (b) 1/9 times (c) 81 times (d) 1/81 times 2. A blackbody at temperature T emits radiation at a peak wavelength . If the temperature of the blackbody becomes 4T, new peak wavelength is (a) 1 256  (b) 1 64  (c) 1 16  (d) 1 4  3. The intensity vs. wavelength distribution of a blackbody is found to have its maximum at the wavelength max   0.1cm. Moreover, the total energy radiated J is measured to be 50 watts. If the temperature of the blackbody is now doubled, the new values of max  and J will be (a) 0.2 cm and 200 watts (b) 0.2 cm and 800 watts (c) 0.05 cm and 200 watts (d) 0.05 cm and 800 watts 4. Planck’ law reduces to Rayleigh-Jeans Law at (a) large wavelength and low temperature (b) small wavelength and high temperature (c) large wavelength and high temperature (d) small wavelength and low temperature 5. Planck’ law reduces to Wien’s Law at (a) large wavelength and low temperature (b) small wavelength and high temperature (c) large wavelength and high temperature (d) small wavelength and low temperature 6. Planck’s radiation formula in terms of angular frequency  can be written as (a) 3 3 3 1 2 1 kT h E d d c e          (b) 3 3 3 1 1 kT h E d d c e          (c) 3 3 3 1 2 1 kT h E d d c e          (d) 3 3 3 1 1 kT h E d d c e          7. If the black body is uniformly heated to a temperature 305 K, the total radiant energy emitted by the body is (a) 2 345W / m (b) 2 491W / m (c) 2 587 W / m (d) 2 695W / m