The coefficient of linear expansion of iron is 0.000011 per K . An iron rod is 10 m long at 27 C . The length of rod will decreased by 1.1 mm , when the temperature of rod changes to ?

1 ) The coefficient of linear expansion of iron is 0.000011 per K . An iron rod is 10 m long at 27 C . The length of rod will decreased by 1.1 mm , when the temperature of rod changes to : -

A ) 11 C  ,                                                            B ) 17 C  , 

C ) 91 C  ,                                                            D ) None of these ,

Correct Answer : -   B ) 17 C  ,

Solution : -

∆ L  =  L˳ α ∆ t   ,

So ,  ∆ t  =  ∆ L  /  L˳ α    ,

∆ t  =  ( 1.1 x 10 ^ ( - 3 ))  /  ( 1.1 x 10 ^ ( - 6 ) x 10 )  ,

∆ t  =  10 .

So ,

T = 27 – 10 = 17 C  ,  Answer .

 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 

2 ) The length of a spring α when a force of 4 N is applied on it and the length is β when 5 N is applied . The length of spring when 9 N force is applied is ?

Solution : -

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .