Sign up now
to enroll in courses, follow best educators, interact with the community and track your progress.
Download
Chapter 1: Temperature-3 (in Hindi)
32 plays

More
In this lesson discuss the Temperature for Railway ALP CBT2 exam.

Vishal Garg
Mechanical Engineer | Unacademy Plus Educator | Railway Category Expert | Follow me to learn Reasoning |

U
Unacademy user
Sir key words ki English bhi Bata dijiye plz
Nirbhay Singh
7 months ago
पूछ लीजिए
Pankaj
7 months ago
Sir from next Lesson plz include during the video itself...thanx for replying
  1. Vishal Garg (B.Tech ME Er.) Star and Verified Educator unacademy SSC and Railway Category Expert


  2. INDI Basic Science & gineering RRB ALP & Technicians Recruitment 2018 for Railway ALP CBT2 Complete Course with MCO By Vishal Garg


  3. Basic Science & for Railway ALP CBT2 Temperature INDIA Engineering RRB ALP & Technicians Recruitment 2018


  4. Thermal Expansion The increase in the dimensions of a body due to the increase in its temperature is called thermal expansion. The thermal expansion of solid is classified as follows: 1. Linear Expansion On increasing the temperature of a solid, its length increases. This increase in length of a solid on heating is called linear expansion. The fractional increase in length per C rise in temperature is called coefficient of linear expansion


  5. 1. Linear Expansion On increasing the temperature of a solid, its length increases. This increase in length of a solid on heating is called linear expansion The fractional increase in length per C rise in temperature is called coefficient oflinear expansion. de coefficient of linear expansion, If is coefficient of linear expansion at t1oC then, 21 - length of the rod at t C 22 - length of the rod at t2 C 11 11 [1 + (t2-ti) then,


  6. 2. Superficial Expansion In increasing the temperature of a solid, its area increases. This increase in area is referred as superficial expansion. If the area of solid at temperature t C is A and on heating the rod, the area becomes A2 at t2 C then, where is called coefficient of superficial expansion at t loc Coefficient ofsuperficial expansion is defined as the fractional increase in area per "C rise in temperature. / AT dA A.dT i.e., Coefficient of areal expansion


  7. 3 Cubical Expansion In increasing the temperature of a solid, its volume increases This increase in volume with increase in temperature is called cubical or volume expansion. IfV1 is the volume of a solid at temperature t, C and on increasing the temperature tot2 C the volume becomes V2 then, . where is coefficient of volume expansion at t oc Coefficient of volume expansion is defined as the fractional increase in volume per "C rise in temperature. dV i.e., Coefficient of volume expansion, Relation between coefficient of linear expansion ( ), coefficient of superficial expansion (B) and coefficient of cubical expansion : : 1:2 :3 2 3


  8. Applications of Thermal Expansion in Solids (i) Bimetallic strip: If two strips of different metals are welded together to form a bimetallic strip, when heated uniformly it bends in the form ofan arc, the metal with greater coefficient of linear expansion lies on convex side. 0 At tc


  9. At t1 c tiOc R. The radius of arc thus formed by bimetal is, or R where t temp. difference between the two ends. d-thickness of each strip oi and 2 are coefficients of linear expansion of two different metals.


  10. (ii) Thermal stress in a rigidly fixed rod: Thermal strain- li 2 stress In elasticity, Young's modulus- Thermal stress-Y (t2-ti) Tensile strain ~aAt (iii) Effect of temperature on pcadulum clock: Change in time period, 7-T2-T,-- . .Ti 2