Question Details

Match the temperature of a black body given in List-I with an appropriate statement in List-II, and choose the correct option. [Given: Wien’s constant as 2.9 × 10−3 m-K and hc/e = 1.24 × 10−6 V-m


List-I List-II
(P) 2000 K (1) The radiation at peak wavelength can lead to emission of photoelectrons from a metal of work function 4 eV.
(Q) 3000 K (2) The radiation at peak wavelength is visible to human eye.
(R) 5000 K (3) The radiation at peak emission wavelength will result in the widest central maximum of a single slit diffraction.
(S) 10000 K (4) The power emitted per unit area is 1 16 of that emitted by a blackbody at temperature 6000 K.
(5) The radiation at peak emission wavelength can be used to image human bones.

Options

A

P → 3, Q → 5, R → 2, S → 3

B

P → 3, Q → 2, R → 4, S → 1

C

P → 3, Q → 4, R → 2, S → 1

D

P → 1, Q → 2, R → 5, S → 3

Show Answer

Correct Answer :

Option C

P → 3, Q → 4, R → 2, S → 1

Solution :

The correct option is P → 3, Q → 4, R → 2, S → 1.


To match each black body temperature in List-I with the corresponding statement in List-II, let us analyze the physical laws involved step-by-step:


1. Wien's Displacement Law:
The peak wavelength λm of radiation emitted by a black body at absolute temperature T is given by:


λm = bT


where b=2.9×10-3 m-K is Wien's constant.


2. Stefan-Boltzmann Law:
The total power emitted per unit area by a black body is proportional to the fourth power of its absolute temperature:


E = σ T4


3. Single Slit Diffraction Central Maximum:
The angular width of the central maximum in single slit diffraction is given by:


β = 2λa λ


Thus, a larger wavelength results in a wider central maximum.


Now, let us evaluate each item in List-I:


Analysis of (P) T=2000 K:
The peak wavelength is calculated as:


λm = 2.9×10-32000 = 1.45×10-6 m = 1450 nm


Among all given temperatures, T=2000 K produces the longest peak wavelength (1450 nm). Since diffraction width is directly proportional to wavelength, this peak wavelength results in the widest central maximum.
P matches with (3).


Analysis of (Q) T=3000 K:
Using Stefan-Boltzmann law, compare the power per unit area emitted at 3000 K to that at 6000 K:


E3000E6000 = 300060004 = 124 = 116


The power emitted per unit area is indeed 116 of that emitted at 6000 K.
Q matches with (4).


Analysis of (R) T=5000 K:
The peak wavelength is calculated as:


λm = 2.9×10-35000 = 0.58×10-6 m = 580 nm


A wavelength of 580 nm lies in the yellow region of the visible light spectrum (400 nm to 700 nm). Therefore, the radiation at peak wavelength is visible to the human eye.
R matches with (2).


Analysis of (S) T=10000 K:
The peak wavelength is calculated as:


λm = 2.9×10-310000 = 0.29×10-6 m = 290 nm


The energy of a photon corresponding to this peak wavelength is:


E = hcλm = 1.24×10-6 V-m0.29×10-6 m 4.28 eV


Since photon energy 4.28 eV≥;4 eV (work function), this radiation can cause the photoelectric emission of electrons from the metal surface.
S matches with (1).


Hence, the correct matching is: P → 3, Q → 4, R → 2, S → 1.

Unlock Our Free Library

Access expert-curated educational resources and study materials—completely free.

Ask AI Tutor
5 left
Q1 View Question & Options
AI Tutor is solving this question...
Reading question context & options...