Electromagnetic Induction and Alternating Current 2 Question 13

14. The two rails of a railway track, insulated from each other and the ground, are connected to a millivoltmeter. What is the reading of the millivoltmeter when a train travels at a speed of $180 km / h$ along the track given that the vertical components of earth’s magnetic field is $0.2 \times 10^{-4} Wb / m^{2}$ and the rails are separated by $1 m$ ? Track is South to North.

$(1981,4 M)$

Show Answer

Answer:

Correct Answer: 14. $1 mV$

Solution:

  1. Potential difference between the two rails :

$V=B v l$ (When $\mathbf{B}, \mathbf{v}$ and $\mathbf{I}$ all are mutually perpendicular to each other)

$$ \begin{aligned} & =\left(0.2 \times 10^{-4}\right) \quad 180 \times \frac{5}{18} \\ & =10^{-3} V=1 mV \end{aligned} $$



NCERT Chapter Video Solution

Dual Pane