KCET2014PhysicsAtomic Physics
In a potentiometer experiment of a cell of emf ( 1.25 ~V ) gives balancing length of ( 30 ~cm ). If the cell is replaced by another cell, balancing length is found to be ( 40 ~cm ). What is the emf of second cell ?
Options
- A( 1.57 ~V )
- B( 1.67 ~V )
- C( 1.47 ~V )
- D( 1.37 ~V )
Correct answer
B. ( 1.67 ~V )
Step-by-step solution
Given, for potentiometer experiment for cell of emf E₁=1.25 , balancing length L₁=30 ~cm . For cell of emf E₂ , balancing length L₂=40 ~cm . We know E L E₁ E₂ = L₁ L₂ 1.25 E₂ = 30 40 E₂=1.25 4 3 =1.666 ~V Therefore E₂ 1.67 ~V Emf of second cell is 1.67