Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Properties of Matter question

2013 · Q141
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /NEET
  3. /Physics
  4. /Properties of Matter
  5. /2013 · Q141

Properties of Matter question

2013 · Q141

NEETPhysicsProperties of MatterMCQ+4 / −1
A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using
  1. A
    Kirchhoff's Law
  2. B
    Newton's Law of cooling
  3. C
    Stefan's Law
  4. D
    Wien's displacement Law
View written solutionFree

Correct answer: D

According to Wien’s displacement law

λmT{\lambda _m}Tλm​T = constant

λm=constantT{\lambda _m} = {{constant} \over T}λm​=Tconstant​

So when a piece of iron is heated, λm{\lambda _m}λm​ decreases i.e. with rise in temperature the maximum intensity of radiation emitted gets shifted towards the shorter wavelengths. So the colour of the heated object will change that of longer wavelength (red) to that of shorter (reddish yellow) and when the temperature is sufficiently high and all wavelengths are emitted, the colour will become white.

PreviousNext

More from Properties of Matter

  • The molar specific heats of an ideal gas at constant pressure and volume are denoted by Cp and Cv, respectively. If γ = Cv​Cp​​ and R is the universal gas constant, then Cv is equal to2013 · MCQ
  • The following four wires are made of the same material. Which of these will have the largest extension when the same tension is applied?2013 · MCQ
  • The wettability of a surface by a liquid depends primarily on2013 · MCQ
  • A slab of stone of area 0.36 m2 and thickness 0.1 m is exposed on the lower surface to steam at 100oC. A block of ice at 0oC rests on the upper surface of the slab. In one hour 4.8 kg of ice is melted. The thermal conductivity of slab is…2012 · MCQ
  • If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q?2012 · MCQ
  • Liquid oxygen at 50 K is heated to 300 K at constant pressure of 1 atm. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time ?2012 · MCQ
  • A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat Q in time t. The metallic rod is melted and the material is formed into a rod of half the radius of the original rod. What…2010 · MCQ
  • The total radiant energy per unit area, normal to the direction of incidence, received at a distance R from the centre of a star of radius r, whose outer surface radiates as a black body at a temperature TK is given by2010 · MCQ