question_answer

A horizontal straight wire 10 m long extending from East to West is falling with a speed of 5 m/s at right angles to the horizontal component of the Earth's magnetic field \[0.30\times {{10}^{-4}}Wb{{m}^{-2}}.\]

(i) What is the instantaneous value of the emf induced in the wire?

(ii) What is the direction of the emf?

(iii) Which end of the wire is at the higher electrical potential?

Answer:

(i) Given.           \[l=10m,\] \[v=5\,m{{s}^{-1}},\]

\[{{B}_{H}}=0.30\times {{10}^{-4}}Wb{{m}^{-2}}\]

\[\therefore \] Instantaneous value of the emf induced in the wire,

\[e={{B}_{H}}lv=0.30\times {{10}^{-4}}\times 10\times 5=1.5\times {{10}^{-3}}V\]

(ii) According to Fleming?s right hand rule, the direction of emf is from West to East.

(iii) Western end of the wire is at the higher electrical potential